1. while still a student = while she was
still a student 还是个学生的时候(状语从句的省略现象)
(you) Don’t talk while (you are) eating.
When (he was) asked how he gained first
place, he suddenly became cheerful.
The boys will go out to play football
whenever (it is) possible.
I won’t go to his birthday party unless (I
am) invited.