—How do you know that he has bought MP5?He wrote e-mail to me yesterday.A. a anB. a

问题补充：

—How do you know that he has bought MP5?

--- He wrote e-mail to me yesterday.

A. a, an

B. an, an

C. a, the

D. the, a

答案：

A. a, an

(答案→)B. an, an

C. a, the

D. the, a

解析：句意:你怎么知道的他买了一部MP5?——昨天他发了一个电子邮件给我。结合语境可知前后两空都是泛指任何一个，MP5和e-mail的词首音素都是元音，故不定冠词用an，选B。