中考英语词语辨析（高频80组）及测试题+答案+ 解析
四十七、must（必须；一定）与have to（不得不）
【辨析要点】
1. 语气与主动性：① must表“必须”，语气强烈，强调主观上的义务或必要性，也可表“一定”（肯定推测）；② have to表“不得不”，语气较弱，强调客观上的压力或无奈（如规则、环境等），无推测含义。
2. 时态差异：① must只有一般现在时一种时态；② have to有多种时态（has to、had to、will have to等）。
3. 否定式差异：① must的否定式是mustn't，表“禁止、不允许”；② have to的否定式是don't have to/doesn't have to，表“不必”，相当于needn't。
【例句】
① You must finish your homework before dinner.（你必须在晚饭前完成作业。——主观义务）
② He must be at home now. The light is on.（他现在一定在家，灯亮着。——肯定推测）
③ I have to get up early tomorrow. I have a meeting.（我明天不得不早起，有个会议。——客观压力）
④ She had to stay at home yesterday because she was ill.（她昨天不得不待在家里，因为生病了。——过去时）
⑤ You don't have to come early. The meeting starts at 1.0 o'clock.（你不必早来，会议1.0点开始。——不必）
⑥ You mustn't smoke here.（这里禁止吸烟。——禁止）
测试题
1. You ______ follow the traffic rules. It's important. A. must B. have to C. mustn't D. don't have to
2. He ______ stay at home because it's raining hard. A. must B. has to C. mustn't D. doesn't have to
3. You ______ run in the hallway. It's dangerous. A. must B. have to C. mustn't D. don't have to
4. She ______ finish the work today. She can do it tomorrow. A. must B. has to C. mustn't D. doesn't have to
5. The light is on. He ______ be at home. A. must B. has to C. may D. can
答案及解析
1. 答案：A 解析：结合句意“你必须遵守交通规则，这很重要”，强调主观上的义务（遵守规则是必要的），用must；have to强调客观压力（此处无客观压力的语境），mustn't“禁止”、don't have to“不必”不符合语境，故选A。
2. 答案：B 解析：结合句意“因为雨下得很大，他不得不待在家里”，强调客观环境（下雨）带来的压力，用has to（主语He是第三人称单数）；must强调主观义务，mustn't“禁止”、don't have to“不必”不符合语境，故选B。
3. 答案：C 解析：结合句意“你不许在走廊里跑，很危险”，表“禁止”，用mustn't；must“必须”、have to“不得不”不符合语境，don't have to“不必”语气过轻，故选C。
4. 答案：D 解析：结合句意“她不必今天完成工作，明天可以做”，表“不必”，用doesn't have to（主语She是第三人称单数）；must“必须”、have to“不得不”不符合语境，mustn't“禁止”语义错误，故选D。
5. 答案：A 解析：结合句意“灯亮着，他一定在家”，表肯定推测，用must；have to无推测含义，may“可能”（推测语气较弱）、can“可能”（用于否定句/疑问句）均不符合，故选A。
