what do we have to wear when the weather is cold.

问题描述:

what do we have to wear when the weather is cold.
是什么从句?再造个类似的句子?为什么要用定冠词修饰weather?

这是一个时间状语从句,当天冷的时候,我们应该穿什么衣服?
What do you have to do when you are in trouble?当你遇到麻烦时,你应该怎么做?
因为特指天气寒冷时,所以在weather前面加定冠词the.