单选题 She ______ be a Canadian because she's got a British passport.
A. can't B. isn't able to C. mustn't D. doesn't need to

【正确答案】 A
【答案解析】[解析] can't be与must be相对，用于否定的推测，对过去动作的否定推测，用can't+不定式完成式。