A. can B. may C. should D. had to
A. must have been B. must be C. can be D. could have been
A. but neither can Charles B. and so Charles can C. but Charles can't D. and Charles can also
A. had better got B. had to get better C. had better to get D. had better get
A. needn't B. may not C. mustn't D. can't
A. could B. would C. must D. might
A. can B. may C. must D. ought
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