Do you want to be healthy? . Smiling can help you stay healthy.A. SmileB. SmilingC. To smi

问题补充：

Do you want to be healthy? . Smiling can help you stay healthy.

A. Smile

B. Smiling

C. To smile

D. Smiled

答案：

(答案→)A. Smile

B. Smiling

C. To smile

D. Smiled

解析：句意：你想健康吗？微笑吧！微笑能帮助你保持健康。结合语境可知本句第二句话为由一个动词构成的祈使句，故用动词原形。选A。