If you don't know the meaning of the word,you can look it up in the dictionary 关于don't
问题描述：
If you don't know the meaning of the word,you can look it up in the dictionary 关于don't
don't为什么不可以用didn"t啊?
答
不可以,这是个条件句,从句部分用一般现在时就可以了,从句子意思上理解可能更容易：如果你不懂...,说的是如果,还没发生,不需要用过去式didn't的