Don’t forget ______ thanks when other people help you.

It is a long time _____I saw you last．——Yes．And it will be a longtime _____ we see each other again．

If there are ______ trees, the air in our city will be _______ cleaner.

I told them not everybody could run as fast as you did, ______?

Now that she is out of job, Lucy ___ going back to school, but she hasn’t decided yet