What’s ______ most useful invention in the 20th century? —______ computer, I think.

Our school has a sports meeting ______ October 15th.

We have sent some books to the children in that village. However, they still need ______.

I feel it hard to keep up with my classmates. But whenever I want to _______, my teacher always encourages me to work harder.

It is ____ that I’d like to go for a picnic.