_ What useful book! _ Is it one that you borrowed from Mr Green yesterday?.A. an theB.

问题补充：

_ What useful book!

_ Is it one that you borrowed from Mr Green yesterday?.

A. an, the

B. a ,an

C. the, /

D. a, the

答案：

A. an, the

B. a ,an

C. the, /

(答案→)D. a, the

解析：不定冠词有a和an两种：a用于辅音音素开头的词前，an用于元音音素开头的词前。The是定冠词，表示特指。