A society cannot be successful if it throws tradition away, but it cannot be successful ____if we do something to stop progress.

Mary is very clever and _____ worth teaching, but her brother is not. Look, he is now _____ asleep in class.

-- Do you think it's a good idea to make friends with your students?--  _____  , I do. I think it's a great idea.

We haven’t heard from her for long, so we give her_____for dead.

Jim went to answer the phone. _____ , Harry started to prepare lunch.