——Let's climb to the top of the tower.——You _____ be joking! I've been afraid of high places since I was a kid.
A. should
B. may
C. can
D. must
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I _____n’t see, now I _____.I _____n’t listen, now I _____.He _____ seem happy, but he _____ be sad.You _____ be kind. You _____ do your best.Can and could. Will and would.May and might, ought to and should.You don’t _____ walk, no you _____n’t.I’m _____ drive, yes I can.We have to, we _____ obey the traffic lights.We can go on green, but we mustn’t on red.Don’t have to and needn’t.Able to and can.Have to and must.Mustn’t and can’t.Modal verbs.
fill in the blanks with proper words and phrases