两者解释都没有差异
但是
while是指一件事发生的过程,一般用进行时
如While I was doing my homework, my sister was playing.
when是指一个瞬间,用一般时就可以了
如When I finished the homework(finished the homework是一瞬间的事), my sisiter was still playing.
通常情况下,两者可以互换