One of our rules is that every student          wear school uniform while at school.

The number of teachers in our school _______ greatly increased last term.A number of teachers in this school ______from the countryside.

.--Your parents were anxious about you. You _____ home without saying a word. -- It’s my fault.

—Is it necessary to look up every new word when I come across it in reading?—No. You ________， because you are likely to guess the meaning from the context.

Mountain climbing ______ be really dangerous at times even though it is challenging and exciting in general.