—May I fish here?
—Sorry, you ________. Look at the sign “No fishing”!
句意：——我可以在这里钓鱼吗？——对不起，你不能。看那个牌子“禁止钓鱼”！
考查情态动词。may可以；mustn’t禁止；can能；needn’t不需要；根据“Look at the sign “Nofishing”!”可知，钓鱼是禁止的，“May I……”的否定回答用can't或者mustn't。故选B。
—May I fish here?
—Sorry, you ________. Look at the sign “No fishing”!
—It’s very cold outside.
—Oh, yes. You’d better________ your coat.
It’s getting dark. You’d better ________ out by yourself. It’s dangerous.
Time is limited! You'd better________your time any more.
We _________ try our best to fight against pollution.
—Sorry, Miss Chen. I missed the early bus, so I was late again.
—It doesn’t matter this time. You ________ leave home 10 minutes earlier than before in future.
We ________ eat or drink in the museum. It is against the rule.
I love the weekends,because I ________ get up early on Saturdays and Sundays.
To my joy, we_________go to the bank. Mary has lent us some money.
——Must I be back home before 6 o’clock?
——No, you ____. Butdon’t be too late.
