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

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：考查定冠词与不定冠词的区别。“Facebook”首字母大写，是地名或公司名，或人名；这里是个网名，不用冠词；第二空：a waste of time 固定搭配，意为“浪费时间”；句意: 起初我不知道Facebook是什么，现在知道是什么。我不得不说，它听起来像是很浪费时间。故B正确。