be to do的用法 與be going to的區別有什么

be to do共有八種用法：表示堅決的命令、表示“計劃”或“安排的事項”、表示“可能性”、表示“意圖”、表示“應該”、表示“注定”“不可避免”“必然發生”、用于虛擬語氣，表示一種假設、有“期待將來”的含義。

be to do 的用法詳解

1.表示堅決的命令，可譯為“必須”。

If you are to be there on time, you had better hurry.要想準時到達那兒，你最好快點。

(2)If all of us are to remain friendly, we must be sincere with one another.要想保持友誼，我們都必須真誠相待。

5.表示“應該”。

(1)You have done so well. You are to be rewarded.你做的很好，你應該受到獎賞。

(2)Such nasty questions are to be avoided.你應該避免這種下流的問題。

(3)You are to call the police.你應該報警。

6.表示“注定”“不可避免”“必然會發生”。

(1)Anne was wondering what was to become of her boy friend, Tommy.安妮不知道她的男朋友托米會出什么事。

(2)The murderer was sentenced to life imprisonment and was never to see his family again.殺人犯被判終身監禁并且永遠不能和家人見面。

(3)She did not think too much of her unkind acts.However，they were to be harmful to herself，too.她對她不友好的行為并沒有想太多，然而，這些行為必將給她帶來不利。

(4)Tom wasn’t worried about his head injury,but it was to be troublesome for him later.湯姆不擔心他頭部的傷，但是以后這損傷必將給他帶來麻煩。

(5)You are to answer for what you have done.你必將為你所做的事承擔后果。

7.用于虛擬語氣，表示一種假設。

(1)If I were to do it, I would do it well.這件事如果我來做，我會做好它。

(2)Even if you were to take a taxi now, you would not be able to arrive at your destinaton on time.現在即使坐出租車，你也不會準時到達目的地的。

8.有“期待將來”的意思。

(1)The actual usefulness of the newly invented equipment is still to be determined.這種新發明出來的設備的實用性如何還有待觀察。

(2)Henry's appointment with the accountancy firm is yet to be confirmed.亨利與這家會計事務所的約定還有待確認。

be to do和be going to的區別

1、am/is/are going to 加動詞原形，表示主語的意圖或打算將來做的事。如：

What are you going to do tomorrow? 你打算明天做什么呢？

The play is going to be produced next month. 這出戲下月開播。

另外：已有跡象表明將要發生的事，只能用 am/is/are going to+動詞原形。如：

Look at the dark clouds; it’s going to rain. 看那烏云，快要下雨了。

2、be to加動詞原形，僅用于表示正式的公務安排、公告指示、義務、禁止等。如：

You’re to deliver these flowers before 10. 你在10點鐘之前把這些花送去。

You are to (=should) report to the police. 你應該報警的。

You’re not to (=mustn’t) tell him anything about our plans. 你不要把我們的計劃透露給他。

注：這與不定式作表語不同：My idea is to go there today. 我的意思是今天就去那里。

3、be to強調客觀安排或受人指示而做某事，be going to則強調主觀的打算或計劃。

4、be about to加動詞原形，表示即將或馬上要做某事。如：

He is about to leave for Beijing. 他馬上要去北京。