At first I didn’t know what Facebook was and now I do know what it is. I have to say it

问题补充：

At first, I didn’t know what Facebook was, and now I do know what it is. I have to say, it sounds like huge waste of time.

A. /, the

B. /,a

C. the, a

D. a, the

答案：

A. /, the

(答案→)B. /,a

C. the, a

D. a, the

解析：考查冠词：句意：一开始，我不知道Facebook是什么，现在我知道它是怎么回事了，我不得不说，这听起来象浪费时间。第一空Facebook前面不加冠词，第二空是词组a waste of time浪费时间，选B。