Выберите форму смыслового глагола, соответствующую данному предложению
1. What problem are you...?
2. We...This problem last week.
3. Did you...this problem in class?
4.This professor often...such problems at his lectures,doesn't he?
5.Does he often...such problems?
6. Why is he...this problem?
7.Shall we... this problem next week?
a)discuss
b)discusses
c)discussed
d)discussing