You don’t seem to enjoy your meal very much.--Not really I’m just.A. on dietsB. o

问题补充：

--- You don’t seem to enjoy your meal very much.

----- Not really, I’m just.

A. on diets

B. on a diet

C. on the diet

D. in a diet

答案：

(答案→)A. on diets

B. on a diet

C. on the diet

D. in a diet

解析：考查与diet有关的固定短语搭配。表示节食on a diet,go on diet