The exam was very easy,wasn't it?

The exam was very easy,wasn't it?
yes,but i don't think ____ could pass it.
答案：B anyboby
解析：somebody 和 everyboby 都用在肯定句,前者表示会有人,后者表示每一个人；anybody 用在否定句,nobaby 表示否定意思,等于 not anybody.本句中 I don'tthink 是由于主句的 think 的要求,把从句的否定转移到主句,因此从句应该按否定处理.
It's difficult to tell the twins one from____
答案：A the other
解析：twins 意思是双胞胎,one 指两个中的其中之一,the other 指另一个,如果用 the others,就变成多胞胎.
This exercise is ______difficult______.
答案：B so;that few of us can do it
解析：
A.so; that few of us can do：that 从句中的谓语动词 do 是及物动词,此处缺少宾语.
C.too; for anyone of us to do：语法没错,但在意思全部否定,即我们任何人都做不了,有些绝对,根据最佳原则,B 表示的“几乎没几个人做得了”,还是留有余地好.
D.too; to do it:too ...to do 表示“太...做不了”,不定式属于句子的附加成分,逻辑宾语是句子的主语,加 it 意思重复.
The city center wasn't so crowed this morning _____it usually is.
答案：D as
解析：这是个 not so ...as ...句型,表示 “A 不如 B 如何”,本句意思是“今天上午市中心不如平时拥挤”.