If you feel tired and sick of fat food, that is you have to go to the hospital f

If you feel tired and sick of fat food, that is ______ you have to go to the hospital for medical examination.

A．why             B．whether           C．when                D．what

试题答案

C

解析:

主要测试表语从句。译文：如果你感到疲惫，而且不喜欢油腻食物，那就是你必须去医院做个检查的时候了。