托福备考只要做到这3件事

托福备考只要做到这3件事（共3篇）

篇1：托福备考只要做到这3件事

GRE阅读备考这3件事都做到再谈高分

GRE阅读备考必练：读懂文章大意

文章结构是做GRE阅读理解题整体思路的关键。掌握了文章结构就知道文章大体的行文脉络，文章的大体意思也差不多了。文章的结构类型以及标志词，以及文章结构类型和主旨题之间的关系，仔细分析一道主旨题的正确答案是怎么阐述原文篇章主旨和结构的，其实这个正确答案就是文章的中心句的改写形式，最重要的就是找出原文中的中心句，这是帮助读者更深刻地理解原文结构的有效办法。

GRE阅读备考必练：熟悉常考题型

俗化说，知己知彼，百战百胜。要想迅速攻克新GRE阅读难关，就要了解出题者的思维。根据题目反推原文考点，题目都考了原文哪些内容，自己有没有关注到这些内容并做标记，这些内容都有什么可总结的规律、特征词。这样总结非常重要，如果坚持下去，很短一段时间后，就会发现一些固定的原文出题点，日后再读原文的时候也就会自然而然地关注它们了。

GRE阅读备考必练：总结分析错题

分析错题，做错的题一定不能放过，看它们与正确答案之间的差别在哪里，在分析错题的同时更要关注正确答案与原文定位处的叙述之间的改写关系，尤其是词与词的对应关系。当然除了这三点外还有很多可以总结的，比如词汇、难句等，总结是提高的关键，特别是在GRE考试的阅读中，只有多总结，从总结中不段进步，不段提高，这样我们的阅读水平才会得到提高。

GRE阅读就是实实在在的“读英文”能力，所以认清了GRE阅读的本质后，紧抓重点，解决方法也就应运而生。

GRE阅读练习每日一篇

(This passage is excerpted from an article that was published in 1981.)

The deep sea typically has a sparse fauna dominated by tiny worms and crustaceans, with an even sparser distribution of larger animals. However, near hydrothermal (hydrothermal: adj.热水的, 热液的) vents, areas of the ocean where warm water emerges from subterranean sources, live remarkable densities of huge clams, blind crabs, and fish.

Most deep-sea faunas rely for food on particulate matter (particulate matter: 颗粒物质), ultimately derived from photosynthesis, falling from above. The food supplies necessary to sustain the large vent communities, however, must be many times the ordinary fallout. The first reports describing vent faunas proposed two possible sources of nutrition: bacterial chemosynthesis, production of food by bacteria using energy derived from chemical changes, and advection, the drifting of food materials from surrounding regions. Later, evidence in support of the idea of intense local chemosynthesis was accumulated: hydrogen sulfide was found in vent water; many vent-site bacteria were found to be capable of chemosynthesis; and extremely large concentrations of bacteria were found in samples of vent water thought to be pure. This final observation seemed decisive. If such astonishing concentrations of bacteria were typical of vent outflow, then food within the vent would dwarf any contribution from advection. Hence, the widely quoted conclusion was reached that bacterial chemosynthesis provides the foundation for hydrothermal-vent food chains—an exciting prospect because no other communities on Earth are independent of photosynthesis.

There are, however, certain difficulties with this interpretation. For example, some of the large sedentary organisms associated with vents are also found at ordinary deep-sea temperatures many meters from the nearest hydrothermal sources. This suggests that bacterial chemosynthesis is not a sufficient source of nutrition for these creatures. Another difficulty is that similarly dense populations of large deep-sea animals have been found in the proximity of “smokers”—vents where water emerges at temperatures up to 350℃. No bacteria can survive such heat, and no bacteria were found there. Unless smokers are consistently located near more hospitable warm-water vents, chemosynthesis can account for only a fraction of the vent faunas. It is conceivable, however, that these large, sedentary organisms do in fact feed on bacteria that grow in warm-water vents, rise in the vent water, and then rain in (rain in: 涌进, 纷纷而至) peripheral areas to nourish animals living some distance from the warm-water vents.

Nonetheless advection is a more likely alternative food source. Research has demonstrated that advective flow, which originates near the surface of the ocean where suspended particulate matter accumulates, transports some of that matter and water to the vents. Estimates suggest that for every cubic meter of vent discharge, 350 milligrams of particulate organic material would be advected into the vent area. Thus, for an average-sized vent, advection could provide more than 30 kilograms of potential food per day. In addition, it is likely that small live animals in the advected water might be killed or stunned by thermal and/or chemical shock, thereby contributing to the food supply of vents.

16. The passage provides information for answering which of the following questions?

(A) What causes warm-water vents to form?

(B) Do vent faunas consume more than do deep-sea faunas of similar size?

(C) Do bacteria live in the vent water of smokers?

(D) What role does hydrogen sulfide (hydrogen sulfide: 氢化硫) play in chemosynthesis?

(E) What accounts for the locations of deep-sea smokers?

17. The information in the passage suggests that the majority of deep-sea faunas that live in nonvent habitats have which of the following characteristics?

(A) They do not normally feed on particles of food in the water.

(B) They are smaller than many vent faunas.

(C) They are predators.

(D) They derive nutrition from a chemosynthetic food source.

(E) They congregate around a single main food source.

18. The primary purpose of the passage is to

(A) describe a previously unknown natural phenomenon

(B) reconstruct the evolution of a natural phenomenon

(C) establish unequivocally the accuracy of a hypothesis

(D) survey explanations for a natural phenomenon and determine which is best supported by evidence

(E) entertain (to receive and take into consideration “refused to entertain our plea”) criticism of the author’s research and provide an effective response

19. Which of the following does the author cite as a weakness in the argument that bacterial chemosynthesis provides the foundation for the food chains at deep-sea vents?

(A) Vents are colonized by some of the same animals found in other areas of the ocean floor.

(B) Vent water does not contain sufficient quantities of hydrogen sulfide.

(C) Bacteria cannot produce large quantities of food quickly enough.

(D) Large concentrations of minerals are found in vent water.

(E) Some bacteria found in the vents are incapable of chemosynthesis.

20. Which of the following is information supplied in the passage that would support the statement that the food supplies necessary to sustain vent communities must be many times that of ordinary fallout?

I. Large vent faunas move from vent to vent in search of food.

II. Vent faunas are not able to consume food produced by photosynthesis.

III. Vents are more densely populated than are other deep-sea areas.

(A) I only

(B) III only

(C) I and II only

(D) II and III only

(E) I, II, and III

21. The author refers to “smokers” (line 38) most probably in order to

(A) show how thermal shock can provide food for some vent faunas by stunning small animals

(B) prove that the habitat of most deep-sea animals is limited to warm-water vents

(C) explain how bacteria carry out chemosynthesis

(D) demonstrate how advection compensates for the lack of food sources on the seafloor

(E) present evidence that bacterial chemosynthesis may be an inadequate source of food for some vent faunas

22. Which of the following can be inferred from the passage about the particulate matter that is carried down from the surface of the ocean?

(A) It is the basis of bacterial chemosynthesis in the vents.

(B) It may provide an important source of nutrition for vent faunas.

(C) It may cause the internal temperature of the vents to change significantly.

(D) It is transported as large aggregates of particles.

(E) It contains hydrogen sulfide.

Throughout human history there have been many stringent taboos concerning watching other people eat or eating in the presence of (in the presence of: adv.在面前) others. There have been attempts to explain these taboos in terms of inappropriate social relationships either between those who are involved and those who are not simultaneously involved in the satisfaction of a bodily need, or between those already satiated and those who appear to be shamelessly gorging. Undoubtedly such elements exist in the taboos, but there is an additional element with a much more fundamental importance. In prehistoric times, when food was so precious and the on-lookers so hungry, not to offer half of the little food one had was unthinkable, since every glance was a plea for life. Further, during those times, people existed in nuclear or extended family (extended family: 大家庭,扩大的家庭(如数代同堂的家庭)) groups, and the sharing of food was quite literally supporting one’s family or, by extension, preserving one’s self.

23. If the argument in the passage is valid, taboos against eating in the presence of others who are not also eating would be LEAST likely in a society that

(A) had always had a plentiful supply of food

(B) emphasized the need to share worldly goods

(C) had a nomadic rather than an agricultural way of life

(D) emphasized the value of privacy

(E) discouraged overindulgence

24. The author’s hypothesis concerning the origin of taboos against watching other people eat emphasizes the

(A) general palatability of food

(B) religious significance of food

(C) limited availability of food

(D) various sources of food

(E) nutritional value of food

25. According to the passage, the author believes that past attempts to explain some taboos concerning eating are

(A) unimaginative

(B) implausible

(C) inelegant

(D) incomplete

(E) unclear

26. In developing the main idea of the passage, the author does which of the following?

(A) Downplays earlier attempts to explain the origins of a social prohibition.

(B) Adapts a scientific theory and applies it to a spiritual relationship.

(C) Simplifies a complex biological phenomenon by explaining it in terms of social needs.

(D) Reorganizes a system designed to guide personal behavior.

(E) Codifies earlier, unsystematized conjectures about family life.

答案：16-26：CBDABEBACDA

篇2：托福备考只要做到这3件事

语言表达要流利

对于短期备考托福口语的小伙伴来说，首先，语言表达方面需要提升流利度，节奏自然，然后具备的一定的语音语调，尤其是重读。

因为如果我们能够流畅地将自己的观点，理由和细节中的关键词重读出来的话，那么考官在get到我们的point方面就会比较直观轻松，而你的答案也就会在表达方面给考官耳目一新的感觉。

不过，想要具备老外那样的语音语调，没有长期练习肯定是难以做到的。

具体练习方法

每天跟读10-20分钟的的英语视频;

不需要每天变化跟读内容，这样因为跟读材料非常熟悉，就比较容易坚持下来。

这个过程中和内容无关，而是通过和原视频对比;

保证口型到位，舌头不打结;

口腔肌肉就会在这样的练习中逐渐打开，说英语就会越来越轻松，那么表达的信心就逐渐来了。

表达内容要熟悉

表达顺畅之后，接下来我们大脑里面还应该有足够多的关于话题和理由方面的积累!在这里小站的机经是一个非常好的材料，我们通过在刷机经的过程中梳理出其中自己常用的理由以及一些不同话题方面自己熟悉的素材。这样考试每当看到独立口语题的时候都会更从容，甚至倍感亲切，然后自然能流利高效输出答案。

然而，很多考生可能还有一个误区：我们都知道在语言使用方面应该尽量少犯一些语法错误，比如说常见的三单，指代的混淆，或者举例子时候时态的错误，同时在句式方面尽可能多样性一些。可是，问题来了，很多学生想着不要犯错结果表述却磕巴起来，越说越没底气。

语言的功能主要一个就是输出信息，所以开口的时候我们只需关注将大脑里面的想法以一定的逻辑并且清楚的表达出来，而无须特别在意是否存在语法问题。这样我们可能节奏和流利度方面都会比较不错，答案的质量也会更高一些。

具体练习方法

将自主练习的内容录下;

回顾自己的音频，着重听语音语调，以及语法错误或者相关句式;

发现自己的问题，并再次调整答案。

按照改善后的方案练习，重新录制音频。

这样经过不断精练的强化和自我修正，语法错误和句式方面很快就会得到改善，形成不用特别注意也不会出错的口语习惯和条件反射。

托福口语和雅思口语有哪些不同之处

首先，形式不同。

托福口语考试为机考，对着电脑单方面输出，还是比较倾向于大多数中国考生熟悉的考试形式。而雅思口语考试则为面试，以跟考官的交流为主，对口语的灵活性要求较高。

再者，数量及内容不同。

托福口语考试的话题则主要落在我们学习生活上，分为6 tasks，即一共就6个题目。这6个题目简单来说分为两大类，第一大类independent tasks独立口语，task 1、2指的就是独立口语，给你一道题目让你准备一下就直接说出你的答案就可以了，考到的都是你熟悉的话题familiar topics;第二大类integrated tasks综合口语，会给你多一些材料例如阅读、听力材料。让你根据你所看到的、听到的去做一些总结、转述以及自身想法的表述，所以考到的是我们的综合能 力，包括我们的阅读能力、听力能力、记笔记能力、概括能力包括最重要的英语语言表述能力。如果再把integrated tasks细分也可以分为task 3、5一类，表述的主要是关于校园场景campus situation，tasks 4、6一类，围绕的较有难度的学术话题academic topics，这也是咱们托福口语成绩单中的分类方法。那另外一种分类方法，就是按照形式来分，task 3、4一类，因为他们又有阅读又有听力;而task 5、6只有一篇听力材料。

而雅思口语考试主要以对话沟通为主，我们是要跟考官进行一对一的互动对话的。其中涉及到的话题包括我们日常生活的方方面面。主要可以分为三大部分，即我们所说的3 parts。part 1是对我们较为熟悉的话题进行双向的交流，主要他问你答。part 2则会稍微难一点，会根据其给定的任务卡准备一分钟时间然后就进行两分钟的个人陈述，在这里是没有和考官的互动的，是你单方面的陈述。最后在part 3会针对part 2处较难的话题较为抽象的话题进行双向讨论，所以在这一环节还是他问你答。

最后，评分标准不同。

在官方给出的评分标准当中，托福口语主要从三大块来评判你的表述，一为语言表达delivery，二为语言运用language use，三为话题展开topic development，在评分的时候主要还是看语言的流利度以及你对话题的掌握及表述能力。

而雅思口语评分则围绕四大方面展开，一为fluency and coherence流利度与连贯性，二为vocabulary词汇，三为grammar语法，四为pronunciation发音。其重要程度也是按照排 序递减的，最重要的为流利度与连贯性，其次词汇语法，在不影响沟通交流的情况下发音不太标准或是有口语是不太影响我们的得分的。

所以，在你具体决定考试考哪一门之前，一定要了解清楚其中的区别，不要将其混为一谈。

托福口语之如何短期内提升口语分数

首先口语的提升绝对不是简单的说的问题，口语的提升是综合问题，你的词汇，句型的掌握，你综合应用词汇句型来按照英美人士的逻辑习惯进行表达。其次即使这些基本的综合应运英语词汇句型来有效表达你意思的方法你掌握了，但是你如果没有输入内容，你还是哑口无言的。比如让我谈谈生物学某一个话题，我立马就傻眼了，因为从来没有学习过这方面知识，不知道如何表达，只是有一些简单的生物方面词汇，生物学的原理不知道如何用英文解释清楚。所以在掌握初步的综合表达技能后，还要加强阅读，听力等输入，让自己知识面扩大，这样口语更有竞争力。

那么了解我分析的以上内容后看看如何短期内提升自己的口语表达水平。

第一就是要把基本的英语表达能力解决。比如常见词汇要熟练掌握，一些常见逻辑词汇要掌握，这样让你的表达更有效。比如in spite of, because of, due to等等词组;还有一些常见词汇的近义词，注意同一个意思的不同表达方式，避免英语中忌讳的重复;还有就是一些句型的掌握，比如it is said/suggested that等等句型，还有就是简答句型和复合句型的转换，让句子更加的多样性，比如He is a Chinese man. He is the man who is from China.(当然这样的不同表达方式表达效果是有区别的，但是短期内及时不能很有效的区分一些细微的区别，但是加以利用，也让托福阅卷人知道你对于英语表达的掌握，是可以用复合句表达更加复杂的意思的能力。)

第二就是在掌握的基础上进行练习。我的经验，英语绝对是Practice makes perfect。熟能生巧。不练习，掌握再多方法也是无用的。短期内根据托福考试的题型，进行分类型的话题训练。比如描述人的话题，你准备一些素材，按照上面准备的词汇，逻辑连接词或词组，复合句型等进行准备和训练。如果这么简单训练以后，也就是托福的独立话题后，你比较熟练后，可以听一些材料然后发表自己的看法，训练自己总结概括的能力，同时进行分析和发表自己观点的能力(这些能力属于高级技能，需要长时间训练，短期内没有效果切莫灰心，坚持练习就会有效果)。

所以短期内通过熟练掌握基本技能，熟悉和准备托福考试常见的内容，可以大大提升英语口语表达的效果，让你可以用简单的词汇流利的，有逻辑的，清晰的表述清楚你的意思。这样你的托福口语分数会获得很大的提升。但是需要提醒的是，这种短期只是一种技巧弥补，真正的英语能力还是我在文章开始讲的，需要掌握基本的综合英语表达技能后，大量输入英文方面的知识，这样你的口语能力才正真得到提升。

★ 这件事真使我什么范文

★ 高考这件事演讲稿

★ 托福阅读如何顺利备考

★ 这件事使我感动

★ 我永远忘不了这件事作文

★ 这件事我永远忘不了作文

★ 这件事教育了我范文

★ 这件事感动在心作文

★ 这件事真让我难忘

篇3：托福备考只要做到这3件事

1、备考阅读不能忽视做题技巧

在托福阅读的答题过程中不仅要掌握科学的备考方法，还需要掌握一些做题的技巧。例如说在议论类型的阅读题当中，我们同学可以按照“一线三定位”方法来解答。

”一线“就是议论文中存在的一条主基线，文章都是围绕这条线来展开。”三定位“就是定位题干关键词、定位与题干想干的段落、定位中心思想找出论证。按照这样的方法去解答议论类型题，我们可以既又准确又快速地解答出题干的答案，也能为其他模块的考试节省下很多时间。

2、备考时间有限，要尽快提高阅读速度

在平时的学习、训练中积极扩大托福阅读词汇量。词汇是学习任何一门外语的基础，如果没有一定的词汇量作为基础，很难想象我们能较为顺畅地去理解一篇英文文章的内容，也就更别提去提升我们的阅读速度了。托福阅读速度的提升一定是要建立在读懂文章的基础之上的。

平时如战时，阅读时注意力要高度集中。如果我们的思维很难与作者想表达的意图产生共鸣，从而从根本上影响我们的阅读质量和速度。长期大量阅读，语言的学习从本质上说有一个渐进的过程，这就决定了我们语言水平的提升要经过一个量变到质变的阶段，而长期大量的阅读就是其中最重要的一点。

3、备考“英语化”，适应考试潮流

在托福阅读的练习过程汇总，英语的思维方式。从宏观层面说，英语思维是一种较为典型的线性思维、结果思维其不同于汉语的点性思维，而我们广大学生在这一点上的相对空白，使得他们在实际的阅读中，要不断地把英文下意识地转化成中文再进行做题判断，进而大大影响做题速度。

针对这一点，我们就必须要下大力气来提高我们的综合英语实力以及语言运用能力。在平时的备考中多多背诵一些习语和惯用搭配，更加深入的了解托福阅读文章。

托福阅读明明都读懂了 为什么还是做不对题

我在任教的这几年里，总会遇到很多学生上来问我：老师，我明明都读懂了，为什么还是做不对题?每当这时候我都会有三道黑线出来。我不想直言ta其实做错题就是没读懂，因为害怕伤了ta的自尊，也害怕那么赤裸的揭露了问题的本质。我会让ta挑选出一个自己刚做错的题，让ta把对应的段逐字翻译给我听。在翻译的过程中遇到错，我就给ta调整，在这个过程中我的目的不仅仅是再一次帮他加深对于错题的理解，更主要的是想让ta发现其实做错题就是自己没有读懂，没有啥别的问题。如果你能理解我上课的中文讲解，你的逻辑其实并没有啥问题。

那有为什么同学总会觉得自己读懂了呢?其实往往这样的同学只是理解了文章的大意但是并不是每一句话都理解了，但是如果想要拿到阅读高分甚至满分真的是每一句话都要理解了，不然总会掉入到ETS的陷阱中。不妨自己逐字的翻译看看吧，然后在比较下参考译文，一定会发现自己理解错误的地方。

做阅读会经历这么几个阶段：

一篇文章错5道题以上，不分题型，时间大概是25-18miny一篇;

一篇错3道题左右，主要是推理 修辞目的 句子插入或者3/6，时间大概21min一篇;

1-2道题错误，可能都是词汇，20min以内做完。

对号入座自己是在哪个阶段，第一个阶段，该去大量背单词;第二个阶段该去理关系;第三个阶段背做错了的词汇题或者镇魂单词。

掌握这3种托福考试阅读技巧 阅读不再难

托福考试阅读技巧一、注重归纳能力的培养

托福阅读最后一大题都是以全文意思的归纳为基础才能完成的，尤其是summary，考察的就是考生对文章的整体把握。因此考生在平时练习的时候一定要注意对文章段落的归纳，能够在较短的时间内把文章段落的中心大意读出来，然后进行总结，最后选择出最能代表文章中心含义的内容。

托福考试阅读技巧二、词汇基础要扎实

托福阅读有一个很大的特色就是有专门考察单词的题型，也就是托福阅读词汇题。从文章中抽出一个单词，让考生选择与这个单词词义最接近最符合的。这些词汇是没有一个大纲让考生去背的，只有靠考生平时自己大量的托福阅读词汇积累，尤其是一些学术学科的词汇。

托福考试阅读技巧三、逻辑关系词要牢记

托福阅读中的英语句子，很多时候是要考生去理解其逻辑关系的，常见的逻辑关系有并列(and, as well)，比较(than, as….as)，因果(because, so, therefore, thus, result from)，递进(also, furthermore)，转折(but, however, yet)等等。找到这些信号词，对你的解题会有很大的帮助。

托福考试阅读技巧 推断题如何解题

托福考试阅读技巧一、逆向推断

这类推断比较明显，往往在关键句当中有能利用的时间，地点，还有具体的取非词，找到之后针对该句的意思取个反就行。

1.The nineteenth century brought with it a burst of a new discoveries and inventions that revolutionized the candle industry and make lighting available to all. In the early-to-mid –nineteenth century, a process was developed to refine tallow with alkali and sulfuric acid. The result was a product called stearin.This breakthrough meant that it was possible to make allow candles that would not produce the usual smoke and rancid odor.

Which of the following can be inferred from this paragraph about candles before the nineteenth century?

A They did not smoke when they were burned

B They produced a pleasant odor as they burned

C They were not available to all

D They contained sulfuric acid.

这句话根据candles定位到第一句话，发现里面有the nineteenth century这个时间点，那题干问的是before the nineteenth century的情况，所以果断取个反选C

2.This was before the steam locomotive, and canal building was at its height. The companies building the canals to transport coal needed surveyors to help them find the coal deposits worth mining as well as to determine the best courses for the canals. This job gave Smith an opportunity to study the fresh rock outcrops created by the newly dug canal. He later worked on similar jobs across the length and breadth of England, all the while studying the newly revealed strata and collecting all the fossils he could find. Smith used mail coaches to travel as much as 10,000 miles per year. In 1815 he published the first modern geological map, “A Map of the Strata of England and Wales with a Part of Scotland,” a map so meticulously researched that it can still be used today.

Which of the following can be inferred about canal building?(2)

○ Canals were built primarily in the south of England rather than in other regions.

○ Canal building decreased after the steam locomotive was invented.

○ Canal building made it difficult to study rock strata which often became damaged in the process.

○ Canal builders hired surveyors like Smith to examine exposed rock strata.

这道题同样根据canal building定位到第一句，在steam locomotive出现之前，cananl building一直是稳坐泰山的地位，而题干问现在canal building怎样，所以取个反，选B。

托福考试阅读技巧二、正向推断

这类推断适应于题干与原文关系属于抽象与具体关系(整体与部分关系)，往往我们解题时要找出相应句子之间的关系。

1.Another major discovery was made in Egypt in 1989. Several skeletons of another early whale, Basilosaurus, were found in sediments left by the Tethys Sea and now exposed in the Sahara desert. This whale lived around 40 million years ago, 12 million years after Pakicetus. Many incomplete skeletons were found but they included, for the first time in an archaeocyte, a complete hind leg that features a foot with three tiny toes. Such legs would have been far too small to have supported the 50-foot-long Basilosaurus on land. Basilosaurus was undoubtedly a fully marine whale with possibly nonfunctional, or vestigial, hind legs.

It can be inferred that Basilosaurus bred and gave birth in which of the following locations (4)

○On land

○Both on land and at sea

○In shallow water

○In a marine environment

本题问Basilosaurus在哪里哺育生命，我们发现原文里没有直接体现相关概念的定位句，但是标红句告诉我们Basilosaurus是一个海洋生物，那试想一下，海洋生物在哪里哺育生命?当然在海里了，所以选D。

2.Even the kind of stability defined as simple lack of change is not always associated with maximum diversity. At least in temperate zones, maximum diversity is often found in mid-successional stages, not in the climax community. Once a redwood forest matures, for example, the kinds of species and the number of individuals growing on the forest floor are reduced. In general, diversity, by itself, does not ensure stability. Mathematical models of ecosystems likewise suggest that diversity does not guarantee ecosystem stability—just the opposite, in fact. A more complicated system is, in general, more likely than a simple system to break down. A fifteen-speed racing bicycle is more likely to break down than a child’s tricycle.

Which of the following can be inferred about redwood forests?(3)

○They become less stable as they mature.

○They support many species when they reach climax.

○They are found in temperate zones.

○They have reduced diversity during mid-successional stages.