– We have done a lot to make our city cleaner, but it’s still not enough.– So we should do ________ to improve it.
— _____—Go along this road to the end.
—What______Jane usually _____in his free time?—She usually goes to the library.
—How long may I _____ the English workbook?—For two weeks.
There is a policeman _____ the bus. He is watching the traffic.
It’s good _____ old people to cross the road.