我以为reducing number的是整个前面这句话，不对，其实就是事件reducing

1.带伴随状语的，主句主语最好是直接放在主句句首，使伴随状语的逻辑主语一目了然。不然会引起逻辑混乱
2.过去时就是过去的动作，在过去就完成了；过去完成时表达的是过去的过去，所以需要与一个过去的时态作对比，也即如果句子里面没有特别明显表达过去的过去或者没有某个动词是过去时态，那么不会出现过去完成时。

The persistent efforts of African American unionists eventually paid off: many became highly effective organizers, "gaining the respect of even racist White unionists by winning victories for White as well as African American workers. "

根据是烟的价格上涨百分之十,per capital sales of cigarettes下降百分之四. 推出的结论是,政府多收百分之十的税,会导致per capital sales of cigarette下降百分之四. assumption是政府多收百分之十的税会导致烟的价格上涨百分之十,其他影响烟的价格的因素不会对烟的价格造成影响.

错因: 句子Although de Ricqlès urged caution, arguing for an intermediate type of dinosaur physiology, a generation of paleontologists has come to believe that dinosaur bone is mammalianlike.意思理解错误, 这句话的意思是尽管de Ricqlès arguing for an intermediate type of dinosaur physiology,但是其他人却has come to believe that dinosaur bone is mammalianlike.

hope 的事情到底是什么 Lies in increase 才是正解

to strengthen the conclusion that it is not likely that, for any species of monkeys, crowding increases aggression as significantly as was seen in rats, 需要其他种类的猴子和实验中的rhesus monkey 进行对比, 最好的对比主题是“aggression”.

要推出严格的环境限制不是经济增长的原因, 需要出现其他可能导致经济增长的因素.

条件2虽然有两个运算法则满足，但是带入1@0答案都等于1，所以条件2是满足的！不能因为人家有两个运算法则就算人家错

shaped so smoothly 不能直接修饰前面的wings shaped 的逻辑注意是前面airplane ，manufactured 。所以要重新重述 wings

主句结构是： manufacturers（主语） have tried to build（谓语） airplanes （宾语）with frictionless wings（宾语补充），理论上如果后面要用, shaped...的话，Shaped的动作发出者要么是是manufacturers,要么是airplanes，然而题目是想说wings, 所以一定要加wings或That从句以免引起歧义，只能选BC，而C里面perfect要用副词形式

根据别处的解析，说gmat近些年来认为so……as to do……不是标准的书面用语，在gmat中看见可以直接排除（老题不算），不知对否？

题目能作对的，但是had thought为什么不对呢？就是在emerged之前科学家这么想的呀，请问这里应该怎么理解

介词短语没有主语，但是加上shifting就是分词短语了，有主语，我觉得有主语好一点，就排除了ABC

B的主句是sun400倍远，能和后面的size一样大形成因果吗，感觉应该是400倍大和400倍远应该都是主句才能表达so的逻辑。把D理解成了原因状语

A 效率激起需求，我觉得应该是效率的提高激起会更好吧？所以我就排除了A

CD网："－ing form can even modify an entire clause as long as the entire clause converted into a noun phrase could function as the subject of the verb that is now in -ing form" －－ 摘自曼哈顿 Chapter 6 Modifiers 比较make sense的说法应该是event reduced number，比前面一整句描述的事情 reduced number 感觉更合适。

Dash is versatile in use and can play the role of a comma, semicolon or a colon. Dash here plays the role of a colon(:) - the colon can be used to provide further explanation for what comes before it. The dash, as a replacement of a colon, plays the same role here.

Without "that", the latter clause ( " at some time....greatly reduced their numbers") does not have much meaningful bearing to the first clause as the author intended. It is required to establish that the scientists believe even the latter clause and hence "that" is required to be repeated.

(A) is implying that our ancestors greatly reduced their own numbers (this is incorrect because it was the event that greatly reduced ancestors). When we have an independent clause followed by a participle phrase (one that starts with a gerund and serves as an adjective clause), the participle phrase modifies the subject of the sentence.