① 篇幅一般比开头段和结尾段长。
② 每段有相应的主题句。
③包含定义、解释、描写，说明主题思想的扩展句可以采用实例、数据或个人经历等写作手段。
④不同种类的段落采用不同的扩展手段。
中间段的常用核心句型
1.Although the popular belief is that…, a current (new / recent) study (survey / poll / investigation) indicates (shows / demonstrates) that….
2.Common sense tells us that….
3.The increase (change / failure / success) in…mainly (largely / partly) results from (arises from / is because of)….
4.The increase (change / failure / success) in…is due to (owing to / attributable to) the fact that….
5.Many people would claim that….
6.One may attribute (ascribe / owe) the increase (decrease / change ) to…, but…is not by itself an adequate explanation.
7.One of the reasons given for…is that….
8.What is also worth noticing is that….
9.There are many (different / several /a number of / a variety of)causes (reasons) for this dramatic (marked / significant) growth (change / decline / increase) in…. First,…. Second,…. Finally,….
10.There is no evidence to suggest that….
11.Why are (is / do / did)…? For one thing,…. For another,….
12.Another reason why I dispute the above statement is that….
13.It gives rise to (lead to / bring /create) a host of problems (consequences).
14.There are numerous reasons why…, and I shall here explore only a few of the most important ones.
15.It will exert (have / produce) profound (far-reaching / remarkable / considerable / beneficial / favorable / undesirable / disastrous) effect (influence) on….
16.A multitude of factors could account for (contribute to / lead to / result in / influence) the change (increase / decrease / success / failure / development) in….
17.In 2000, it increased (rose / jumped / shot up) from 5 to 10 percent of the total (to 15 percent / by 15 percent).
18.By comparison with 2002, it decreased (dropped / fell) from 10 to 5 percent (to 15 percent / by 15 percent).
19.It accounts for 15 percent of the total.
20.There were 100 traffic accidents in April, an increase of 5 percent in a five-month period.
21.By 2002, only (less than / more than / almost / about / over/ as many as) three quarters (40 percent of / one out of five / one in four) college population (graduates / housewives) as against (as compared with) last year (2002) preferred to (liked)….
22.With the development (improvement / rise / growth / general recognition / acknowledgement / realization) of…, vast changes awaits this country’s society.
23.Now people in growing (ever-increasing / significant) numbers are beginning (coming / getting) to believe (realize / recognize / understand / accept / see / be aware) that….
24.According to a(n) recent (new / official) study (survey / report / poll),….
25.History (Our society) is filled (abounds) with the examples of….
26.The story (case / instance / situation) is not rare (isolated / unique), it is one of many examples (typical of dozens).
27.A (one) recent (new / general / nationwide) study (survey / poll / investigation) conducted (taken) at a university by (officials / scientists / experts) indicates (reveals / suggests / shows / proves / demonstrates) that….
28.According to (As can be seen in / As is shown in) the figures (statistics / findings / data / graph / table) released (provided) by the government (an institute), it can be learned (seen / predicted) that….
29.There is (no) good (every / little / sufficient / considerable / strong) evidence (proof) to
30.Personal experience (Examples I heard / read of) leads me to conclude that….
31.We must admit the undeniable fact that….
32.No one can deny (ignore / doubt / overlook / obscure / brush aside) the fact that….
33.Experience (Evidence) suggests (shows) that….
34.Take for example…who (that)….
35.The same is true of….
36.As the saying goes,“….”
三、结尾段
结尾段的核心句型
1.From what has been discussed above (Taking into account all these factors / Judging from all evidence offered), we may safely draw (reach / come to / arrive at) the conclusion that….
2.All the evidence (analysis) supports (justifies / confirms / warrants / points to) a(n) unshakable (unmistakable / sound / just) conclusion that….
3.It is high time that we place (lay / put) great (special / considerable) emphasis on the improvement (development / increase / promotion) of….
4.It is high time that we put an end to the deep-seated (unhealthy / undesirable / deplorable) situation (tendency / phenomenon) of….
5.We must look (search / call / cry) for an immediate action (method / measure), because the present (current) situation (phenomenon / tendency / state / attitude) of…, if permitted (allowed) to continue (proceed), will surely (certainly) lead to (result in) the end (destruction / heavy cost) of….
6.There is no easy (immediate / effective) solution (approach / answer / remedy) to the problem of…, but…might be useful (helpful / beneficial).
7.No easy method (solution / recipe / remedy) can be at hand (found / guaranteed) to solve (resolve / tackle) the problem of…, but the common (general / public) recognition of (realization of / awareness of / commitment to) the necessity (importance / significance) of…might be the first step towards change (on the right way / in the right direction).
8.Following these methods (suggestions) may not guarantee the success in (solution to)…, but the pay-off will be worth the effort.
9.Obviously (Clearly / No doubt), if we ignore (are blind to) the problem, there is every chance that….
10.Unless there is a common realization of (general commitment to)…, it is very likely (the chances are good) that….
11.There is little doubt (no denying) that serious (special / adequate / immediate / further) attention must be called (paid / devoted) to the problem of….
12.It is necessary (essential / fundamental) that effective (quick / proper) action (steps /measures / remedies) should be taken to prevent (correct /check / end / fight) the situation (tendency / phenomenon).
13.It is hoped (suggested / recommended) that great (continuous / persistent / sustained / corporate) efforts should be made to control (check/ halt / promote) the growth (increase / rise) of….