These young trees must .
--- He hasn’t watched the movie “ So Young”, has he? --- ______. He told me it was very moving and interesting, he’d like to watch it again.
The world’s population is getting larger and larger, so scientists are trying to _______ new ways to solve the food problem.
Now more and more people ________ sending e-mails ________ letters.
He is ______ excited to hear the good news.
.Not all the students sitting in the back row can see the words on the blackboard _________.