—Must I buy lunch at school?—No, you needn’t. You __________ bring your own lunch if you want to.

—Must I finish my homework at school?— No, you_____. you can do it at home

—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.

Johnny, you _________play with the knife, you_________ hurt yourself. 

You may get lost easily in big cities like Beijing        you have a map or a guide.