There are many CD-ROMs in the bookshop. I don’t know to buy.A. whatB. whichC. whenD. how

问题补充：

There are many CD-ROMs in the bookshop. I don’t know to buy.

A. what

B. which

C. when

D. how

答案：

A. what

(答案→)B. which

C. when

D. how

解析：词义辨析。句意：书店里有许多光碟。我不知道买哪个。所以选B，which作buy的宾语。