Question

when i ___(walk) in the street,i met her.

Answer 1

when i _was walking__(walk) in the street, i met her

when引导的是一个时间状语从句,表示过去某个时刻正在进行的动作.主句不是过去进行时,而是过去时,表示过去发生的一件事或做的一个动作.
when I was walking in the street,I met my best friend这句话的意思是,我正在路上走时,遇到了我最好的朋友.

如果帮到你,请记得采纳,O(∩_∩)O谢谢