be动词原级用在什么地方

be动词原级用在什么地方

应该是be动词原形，而不是原级。be动词原形跟其他动词原形一样，可以用于以下场合：
一、be用作连系动词：
❶ be用作谓语动词
1. 跟情态动词搭配，用作谓语动词。
He can be a good student.他可以成为一个优秀学生。
I may be at home tomorrow all day.明天我可能整天在家。
She suggested that John (should) be a good husband.她建议约翰做个好丈夫。

2. 祈使句中，直接用原形。
Be here early tomorrow morning.明天上午早些来。
Don't be lazy, boy. Be diligent, will you?不要懒惰，小伙子。勤奋起来，好吗？

3. 用于whether引导的让步状语从句中，be用原形。
As a matter of fact, all people, whether they be young or old, are required to be citzens of high ideals, strict disciplines, good education and social morality.事实上，要求所有人，不管老少，都要成为具有崇高理想、严格纪律、良好教育和社会道德的公民。
All countries, be they (=whether they be) big or small, strong or weak, should be equal.国无大小、强弱，应该平等。

❷ be用作非谓语动词
“to be + 表语”结构用作不定式，具有不定式性质的特征，在句子中可以作主语、表语、宾语、补足语、定语、状语等。
To be honest is very important for everyone who wants to get a good job when they are interviewed.面试时诚实对每个想得到好工作的人来说很重要。(主语)
His ambition is to be a doctor when he grows, which his parents think can be achieved because he is interested in medicine.他的大志就是长大以后当医生，他父母认为这是可以实现的，因为他对医学感兴趣。(表语)
What he wants to be is to turn teacher when he grows up, for he is enthusiastic in staying with children and caring about them.他长大后想成为老师，因为他热心跟孩子在一起，并且照顾他们。(宾语)
What do you want me to be?你想我当什么？(宾语补足语)
He is the first person to be here today.他是今天第一个到这儿的人。(定语)
He works hard in order to be a millionaire.他拼命干活想成为百万富翁。(状语)

二、be用作助动词
用作助动词的be主要是用于be doing进行时和被动语态中。
1. 跟情态动词搭配，用于谓语动词中：
He may be watching TV now.他现在可能在看电视。(进行时)
Tom must be punished for what he did.汤姆必须为他的行为受惩罚。(被动语态)

2. 非谓语动词中，to be doing表示不定式的进行式，to be done表示不定式的被动式。这两个结构同样具有不定式的一些基本性质特征，也就是说在句子中做主语、表语、宾语、补足语、定语、状语等。
❶ 不定式的进行式主要表示与谓语动作同时发生且正在进行的动作。
He seems to be recovering.他看来在康复。

When he came in, I happened to be lying on the bed, reading. 他进来的时候，我碰巧正躺在床上看书。

❷ 正如可用进行时态表示将来意义一样，不定式的进行式有时也可表示将来。
It appears to be raining. 似乎在下雨。
The old man seems to be dying. 这老人似乎要死了。
He was happy to be coming home. 就要回家了他感到高兴。
He pretended to be reading an important paper when the boss entered.老板进来时他假装在看一份重要的文件。

❸不定式的逻辑主语是不定式所表示的动作的承受者而非发出者时，不定式一般要采用被动形式(to be done). 语法功能：
It is an honour for me to be askedto speak here.请我在此讲话，我很荣幸。(主语)
She asked to be sent to work inXinjiang.她要求派去新疆工作。(宾语)
He wanted the letter to be typed at once.他要求把信马上打印。(复合宾语)
She didn't like herself to be praised like that.她不稀罕她受这样的表语。(复合结构)
The books are not allowed to be taken out of the room.这些书不许带出这间房子。(主语补足语)
Are you going to the meeting to be held in the teachers' office?你去参加在老师办公室进行的会议吗？
She was too young to be assigned such work.她太小不能派去做这样的工作。(状语)
The next thing to be done is to carry away the earth.下-步要做的事是把土运走。(定语)

祈使句中要用be动词原形，除此之外不定式和情态动词后面也要用原形
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