It's raining heavily ( )the farmers keep on wo-rking in the field.

问题描述:

It's raining heavily ( )the farmers keep on wo-rking in the field.

when

while

while
因为while用在句子中间有对比的含义
前面是雨下的很大
后面是说农民们仍然在田间干活
所以有对比的含义

but