put the verbs right form
1. I saw Tom who (to cross) the street yesterday.
2, When they (to reach) the weather had already changed.
3, The students (to get acquainted) with the new classmate last week.
4, The students expressed their points of viewwhile they (to discuss) the problem.

1. I saw Tom who was crossing the street yesterday. 2, When they reached the weather had already changed. 3, The students got acquainted with the new classmate last week. 4, The students expressed their points of view while they were discussing the problem.