We can do a lot to stay healthy. we should eat a balanced(平衡的) diet.A. At a timeB. In fa

问题补充：

We can do a lot to stay healthy. , we should eat a balanced(平衡的) diet.

A. At a time

B. In fact

C. First of all

D. All together

答案：

A. At a time

B. In fact

(答案→)C. First of all

D. All together

解析：词语辨析。句意：为了保持健康我们做了很多。首先，我们应该保持饮食平衡。根据句意可知，C符合题意。