—Did the book provide the information you need? —Yes. But ________ it, I had to read the whole book.

– It’s difficult for the village children to cross the river to get to school.– We think a bridge ________ over the river.

Mom, the telephone is ringing. I guess either you or Dad           on the phone.

Every year lots of trees _______ to make our country more beautiful.

— Sixteen –year-olds should ____ to drive.