1 He admits that he is more apprehensive for his own safety than that of his family.

这个比较分句补全后为：

He admits that he is more apprehensive for his own safety than he is for that of his family.

than分句的主语和谓语动词he is与主句相同，可以省略。作表语的形容词为比较对应项是必须省略的，但表语形容词的补足语与主句不同，必须保留。形容词的补足语为for介词短语，所以for不能省略。

Forrester has never done any campaigning and never will. 这句话没有问题。will后省略了do it.此时will必须重读，中位状语never必须位于重读的操作词之前。

Advice is like snow：the softer it falls，the longer it will dwell upon，and the deeper it will be sinking into the mind. 这是作者用雪渗入土壤比喻建议被人接受，所以用了sink into the mind.  thinking into the mind 本身就是逻辑混乱的。

2 Data has shown that more Hispanic and black students are majoring in computer science and engineering than _______.

A. those are being hired

B. are being hired

C. being hired

D. hired

本句主句的比较短语为more Hispanic and black students，其对应项在从句中做主语是必须省略的，所以than后应该为谓语动词。由此排除A、C二项。虽然比较分句谓语为被动语态时有时可以省略助动词be，但这与谓语动词有关，如plan，expect，think，admit，intend，realize,  predict等的被动语态常省略be而只保留过去分词。但hire不属于此类动词，其被动语态不可以省略be的。所以排除D，B为正确答案。(关于be的省略可以参考剑桥英语语法P.1111。)

GMAT考题

Analysts blamed May's sluggish retail sales on unexciting merchandise as well as the weather, colder and wetter than was usual in some regions, which slowed sales of barbecue grills and lawn furniture

(A) colder and wetter than was usual in some regions, which slowed

(B) which was colder and wetter than usual in some regions, slowing

(C) since it was colder and wetter than usually in some regions, which slowed

这个题其实是考察than usual的含义和用法。than usual现在基本成了习语，但其实它是比较分句的简略。than usual=than is usual. 省略的是一般现在时的is，因为usual有下面用法：It is usual for somebody to do something. it为形式主语，不定式复合结构为外置主语（真正主语）。该句意思是这个五月份的天气比通常五月份的天气冷且多雨。比较的是通常五月份，than从句省略的是一般现在时系表结构的系词is，而不是was。所than usual通常省略系词be，但补上be不算错，但不能是was。A项的错误在于was，C项的错误在于since这个状语从句修饰谁说不清楚，且同样存在was的时态错误。正确答案为B，补全的than分句为：

which was colder and wetter than it is usual for it to be in some regions, slowing

不定式复合结构中的to be的表语为比较对应项，必须省略，不可补全。to be的逻辑主语for it指代the weather.然后这个比较分句可以省略，第一步省略形式主语it 和外置的不定式复合结构，得到：

which was colder and wetter than is usual in some regions, slowing...

在than is usual 这个系表结构中，当表语为某些形容词时，系词be可以进一步省略，例如necessary，possible，normal，usual等。于是进一步省略is，则得到：

which was colder and wetter than usual in some regions, slowing...