I was out of town at that time, so I don’t know exactly how it ______.

A．was happening

B．happened

C．has happened

D．happens

西洋参的功效（）

A.补中益气，生津养血 

B.大补元气，补脾益肺，生津止渴，安神益智 

C.化瘀止血，消肿定痛 

D.补气生津 

E.补气养阴，清火生津