In addition to keeping on taking exercise Alan is also going on diet to lose weight.A.

问题补充：

In addition to keeping on taking exercise, Alan is also going on diet to lose weight.

A. an; a

B. an; /

C. /; /

D. /; a

答案：

A. an; a

B. an; /

C. /; /

D. /; a

解析：考查冠词。句意 除了继续锻炼之外，安拉了也在进行节食减肥。Take exercise 锻炼 固定短语。Go on a diet 节食。所以选D项。

考点 :考查冠词