It is ten months since he ______ a doctor

In our school library there ____ a number of books onscience and the number of them ____ growing larger and larger.

The detective interviewed Jill and Jenny. They both denied _____ the car.

Driving in rush hour traffic ______ be very dangerous, so you _____ be too careless.

Every pupil has his own potential so it is not proper to _____them ____two kinds．