If it doesn't rain tomorrow ,I'll go hiking.为什么用doesn't而不用isn't?

问题描述:

If it doesn't rain tomorrow ,I'll go hiking.为什么用doesn't而不用isn't?

rain是Do类实义动词原型,否定用don not rain或does not rain.若用is not则后面加raining构成现在进行时,但是不符合句子的意思,所以用does not