Is_______ necessary to learn another language? — I think so.

When did you _________ the Chinese Young Pioneers?

Don’t copy others’ work. If you do it by ________, you’ll feel much better.

If you can’t decide which of the two novels to borrow, why don’t you take_____? —- I won’t read them this month.

I can see some pears ____ the tree,and a bird is ____ it, too.[ ]