Jack described his father,who _____a brave boy many years ago,as a strong-willed man.答案给的是must have been.答案是没错,的确合情合理说的过去.可是选项中还有must be 为什么不行?有人说must be是对现在的推测,可

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Jack described his father,who _____a brave boy many years ago,as a strong-willed man.答案给的是must have been.答案是没错,的确合情合理说的过去.可是选项中还有must be 为什么不行?有人说must be是对现在的推测,可
Jack described his father,who _____a brave boy many years ago,as a strong-willed man.
答案给的是must have been.答案是没错,的确合情合理说的过去.可是选项中还有must be 为什么不行?有人说must be是对现在的推测,可是从语法角度看填must be 没有任何错误,为什么不能填must be?句子中有many years ago存在,那么和must be用在一起,也是表示对过去的推测.

Jack described his father,who _____a brave boy many years ago,as a strong-willed man.答案给的是must have been.答案是没错,的确合情合理说的过去.可是选项中还有must be 为什么不行?有人说must be是对现在的推测,可
must have done表示对过去的推测
must be 现在的推测
就是因为 many years ago“多年前”
才选must have done

must have done 这是一个固定的搭配，对过去的肯定

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“must+不定式的完成式”常用在肯定句中,表示对过去发生的行为的推测,意为"一定;想必"。
例如:
Nonsense, you must have misheard.
胡说，你肯定是听错了。（对过去的推测，很有把握的推测。）
His watch must have stopped. I will go and call him.
他的手表肯定是停了。我去叫他。
He must have been looked down upon by his contemporaries.
他一定是受到同龄人的轻视了。
You must have seen the film Titanic.
你一定看过电影《泰坦尼克号》。
He must have been to Beijing.
他肯定去过北京。
It must have rained last night, for the ground is wet.
昨天晚上一定下过雨了,因为地面是湿的。
It is 8 o’clock. They must have arrived now.
8点了。现在他们一定已经到了。

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Jack described his father, who _____a brave boy many years ago, as a strong-willed man.
答案给的是must have been。答案是没错，的确合情合理说的过去。可是选项中还有must be 为什么不行？有人说must be是对现在的推测，可是从语法角度看填must be 没有任何错误，为什么不能填must be?句子中有many years ago存在，那么和must be用在一起，也是表示对过去的推测
答：情态动词must除了表示“义务”，意为“必须”外，还可能表示“推测”。
推测有两种形式：
1. 对现在和将来的情况的推测用must be+表语或must be+doing, 前者表示：XX一定是。。。、一定在。。（XX地方），后者表示：XX一定在做什么。
如：He must be a student. 一定是个学生。
2. 对过去情况的推测判断：must have done sth.
译：杰克将他父亲描述成一个意志坚定的人。他父亲多年以前一定是一个勇敢的孩子。

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Every Jack has his Every jack has his Jack described his father,who___a brave boy many years ago,as a strong-willed man.A.would be B would have been C must be D must have been.我最想问的是,为什么C Jack described his father,who___a brave boy many years ago,as a strong-willed man.A.would be B would have been C must be D must have been.我最想问的是,为什么C Police described him as a male in his early twenties. Every Jack shall have his Every Jack shall have his jack lived t____with his parents —what is Jack doing?—He is inviting his f—what is Jack doing?—He is inviting his friends ( )join in his birthday party.A.to B.不填 C.for His name is Jack London.Jack is his______ name? His first name is jack.对jack进行提问 jack has already finished his homework .否定句 jack-----------------hishomework ----------- 3.I( )have watched that movie—it`ll give me horrible dreams A.shouidn`t B.needn`t C.couldn`t D.mustn`t4.Jack described his father ,who()brave boy many years ago,as a strong-willed man.A.would be B.would have been C.must be D.must have been5.--Sorry Jack described his father,who _____a brave boy many years ago,as a strong-willed man.答案给的是must have been.答案是没错,的确合情合理说的过去.可是选项中还有must be 为什么不行?有人说must be是对现在的推测,可一道单选must have been 和would have been的区别?Jack described his father, who _______a brave boy many years ago, as a strong–willed man A. would be B. would have been C. must be D. must have been 我不能理解为什么不能用would表示 His first name is jack （His first name is jack（）（）his first name? Jack works in a factory.The factory is f() from his house.全文在下……Jack works in a factory.The factory is f()from his house.So he gers uo very early and leaves home earlier than any otherw() in his factory.He usually f() his breakfast at 6:3 jack,with his father,______shopping every Sunday Jack looked at his father in s( )