It has been widely accepted that only when the students take an active part in the class activities _______ the most effective.
---What do you think made the woman so upset? --- _____ weight.
----That must have been a long trip. -------Yeah, it______ us a whole week to get there.
_______you’ve tried it, you can’t imagine how pleasant it is.
While watching television, ________.
.It was so dark in the cinema that I could hardly ________ my friend.