三、结构省略陷阱

1. —Who has eaten all the cake, Jim?

— Oh, _________ must your two pet dogs.

  A. it                       B. they                   C. that                  D. which

【分析】许多学生可能认为此题应选B，因为其后的your two pet dogs为复数。但实际上，此题的最佳答案就是A，此句实为强调句型It must be your pet dogs that have eaten all the cake 的省略形式。

2. If you are planning to spend your money having fun this week, better _________ it—you’ve got some big bills coming.

A. forget                  B. forgot                C. forgetting          D. to forget

【分析】此题最佳答案为A。考查had better后接动词原形的用法。但是考题中将you had better这一结构省略成better，致使许多同学一时看不出来。又如：

Better go with him. 最好同他一起去。

Better have the operation right now. 你最好还是现在就动手术。

3. Why _________ skating there with us this afternoon?

A. don’t go              B. not to go            C. not go              D. go not

【分析】许多学生会认为否定式须在go前加助动词及否定词或在不定式的小品词to前加否定词，从而将答案误选为 A 或B。其实，此题答案应该选C。当询问情况、提出建议或征求意见时，人们通常将Why don’t you do… 省略成Why not do…，故答案选 C。

四、状语从句省略陷阱

为了简洁起见，有的状语从句(如时间状语从句、条件状语从句、方式状语从句等)有时可省略从句的主语和部分谓语(尤其是当从句主语与主句主语一致，且从句谓语包括有动词be时)：

While (he was) waiting, he saw Jim pass by. 他在等时见到吉姆路过。

He opened his mouth as if (he was) to speak. 他张开口好像要说话似的。

Often she would weep when (she was) alone. 她一个人时，常常哭泣。

I’d like to see you whenever (it’s) convenient. 你方便时我想来看看你。

有些由if构成的省略结构，已属固定短语，如if any, if necessary, if possible, if not, if so。如：

There are few, if any, mistakes in that book. 那本书就是有错误也不多。

If necessary, ring me at home. 如果必要，可以打电话到我家找我。

If possible, I wish to come next time. 如果可能，我希望下次能来。

He may be busy. If so, I’ll call later. If not, can I see him now? 他可能很忙，要是这样，我以后再来拜访。要是不忙，我现在可以见他吗?