__you want to learn another language,you must learn the words first.

问题描述:

__you want to learn another language,you must learn the words first.
___中是填when还是填if?
我怎么觉得两者都可以呢?但答案只有一个..

填If更好,强调后半句是前半句的必要条件
When语法上没错,但没有if的语感