My brother wants to be engineer when he grows up.A. aB. anC. theD. /

问题补充：

My brother wants to be engineer when he grows up.

A. a

B. an

C. the

D. /

答案：

A. a

(答案→)B. an

C. the

D. /

解析：当他长大后，我的弟弟想要成为一名工程师。结合语境可知本句泛指任何一名工程师，故用不定冠词。Engineer词首音素是元音，故不定冠词用an。选B。