Ⅰ. must “必须”，往往着重于主观上认为有义务，有必要。
① We must work hard. 我们必须努力工作。
② Imust go. 我必须走。
Ⅱ. have to “必须”往往着重于客观的需要，含有“不得不”的意味。如：
① Do you have to see a doctor today? 你今天要去看医生吗
② It was late and we have to stay at home. 时间已晚，我们只得呆在家里。
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