When a pencil is partly in water it looks as if it.A. breaksB. has brokenC. were brokenD.

问题补充：

When a pencil is partly in water, it looks as if it.

A. breaks

B. has broken

C. were broken

D. had been broken

答案：

A. breaks

B. has broken

(答案→)C. were broken

D. had been broken

解析：考查虚拟语气。连词as if后面的从句有两种情况，如果陈述的是真的事情，那么使用陈述语气，如果表示的是虚假的事情，那么使用虚拟语气。与现在或将来相反，用一般过去时的时态。句意：当一支铅笔部分在水里的时候，它看起来就好像是被折断的一样。实际上铅笔并没有被折断，这是假的事情，故使用一般过去时表示虚拟语气。