課本中不會教你的[B]105　be about to do sth. 和be to do sth.

105　be about to do sth. 和be to do sth.

① be about to do sth.表示“正要做某事，馬上要做某事”，主語一般是人，時間距離很近（immediate future），后面不可跟表示將來時間的狀語，如soon，at once，immediately。be about to do 后還常跟when 從句，相當于just at this time，也可以是 was doing…when（正在做……這時），had done…when（剛剛做……這時）。

I was just about to leave when the telephone rang. 我正要離開時，電話鈴響了。

I was writing a letter when the light went out. 我正在寫一封信，這時燈熄滅了。

We had just started our work when the machine broke down.我們才剛剛開始工作，這時機器就壞了。

I was walking down the road when a bird flew past overhead. 我正在路上走著，這時一只鳥從頭頂上飛過。

They are about to leave soon.

They are about to leave.

他們就要動身了。

② be+to do sth.表示預先的安排或計劃，也表示命令、指示、勸告等。主語一般是人，有時可以是物。

The foreign friends are to arrive this evening. 外國朋友定于今天晚上到達。（安排）

Father is to return next month. 父親將于下個月回來。（計劃）

The plan is to be made in a week. 計劃將在一周內做好。（計劃）

You are not to walk on the grass. 不許踐踏草坪。（命令）

You are to be criticized if you do like that. 你那樣做就會受到批評。（警告）

All the exercise-books are to be handed in after class. 所有的練習本都必須在課后交上來。（要求）

She was to have left earlier，but it rained. 她本打算早些離開的，但是卻下雨了。

提示

①be to do sth. 用于第二人稱時，有時表示“應該，理應”的含義，相當于should。

You are to give her more help. 你應該給她更多的幫助。

You are to study harder. 你應該更努力地學習。

②be to do sth. 也可以是表語結構。

Her duty is to keep the hall clean and tidy. 她的職責是保持大廳整潔。

One of the most urgent things to do now is to get enough money. 現(xiàn)在要做的最緊迫的事情之一是弄到足夠的錢。