There isdesk in the room.old book is on it.A. a; AB. a; AnC. An; aD. an; A

问题补充：

There isdesk in the room.old book is on it.

A. a; A

B. a; An

C. An; a

D. an; A

答案：

A. a; A

(答案→)B. a; An

C. An; a

D. an; A

解析：句意：在房间里有一张课桌。一本旧书在桌子上。desk是以辅音开头的单词，所以前面应该用不定冠词a;故排除CD；第二空old是以元音开头的单词，故选B。