单选题 How can he do so much work? He ______ stay late at the office every evening and take work home at weekends.
A. must B. might C. can't D. would

【正确答案】 A
【答案解析】[解析] Must的肯定语气最强。根据句子含义，应选最肯定的，所以选项A是正确的。