1、表“必须”。 You must talk to them about their study.你必须同他们谈谈关于他们学习的事。 2、在否定结构中表不许。 You mustnt leave here.你不能离开这儿。 3、表坚定的建议。You must come and see us as soon as you get to Shanghai.一到上海你得马上来看我们。 4、表推测...