In the crosslake swimming race, a boat will be ________ in case of emergency.

I like to spend time mygrandparents on Sundays.

It’s very difficult _____ the child ______the work in time. Let’s go and help him.

How do you keep fit?—By having a healthy diet and _________ regularly.

Five years ago， only one car in the village. Now there are five cars. And in five years， more cars in the village.