I will give the message to him he comes back.　　A. beforeB. sinceC. as soon asD. until

问题补充：

I will give the message to him he comes back.

A. before

B. since

C. as soon as

D. until

答案：

A. before

B. since

(答案→)C. as soon as

D. until

解析：本题考查由as soon as引导的时间状语从句的用法。主句是将来时从句用一般现在时，故选C。