情態動詞ought to的用法歸納

1. 表示義務或責任

表示義務或責任，意為“應該”：

You ought to work harder. 你應該更努力工作。

Teachers ought to be honored. 教師應當受到尊敬。

Every citizen ought to obey law. 每個公民都應守法。

2. 表示建議或勸告

2. 表示建議或勸告，意為“應該”：

There ought to be more buses during the rush hour. 高峰期間應公共汽車該多發幾輛。

You ought to see her new film. 你應該看看她新拍的電影。

We oughtn’t to take risks. 我們不宜于冒險。

3. 表示推斷

3. 表示推斷，意為“應該”、“可能”：

(1) ought to + 動詞原形，表示對現在或將來情況的推測。如：

Prices ought to come down soon. 價格可能會很快下跌。

If he started at nine, he ought to be here by now. 要是他九點鐘出發，現在該到了。

That ought to be enough food for all of us. 那些該夠我們大家吃的了。

(2) ought to +進行式，表示對正在發生的情況的推測。如：

You oughtn’t to be talking so much. 你不該講這么多話。

You ought not to be sitting here. It’s for old man only. 你不該坐在這兒，這是老人專座。

You ought to be wearing your shirt. 你該穿襯衫。

(3) ought to +完成式，表示對過去情況的推測；也可表示過去本該發生而實際上未發生的情況：

The table-tennis game ought to / should have finished by now. 乒乓球比賽現在應該已經結束了。

There are many books which I ought to have read, and still ought to read. 有許多書我過去就應該看的，現在還應該看。

I ought to have helped her，but I never could. 我本該幫助她的，卻從未能這樣做。

You ought to have come earlier. 你本該來得早一點兒。

She ought to have been a teacher. 她本該當教師。

4. ought to用于否定句和疑問句

在否定式中用ought not 或oughtn’t，在疑問中將ought提到主語之前。如：

They ought to go now, oughtn’t they? 他們現在該走了，是嗎?

Ought we (to) be in Taipei by now? 他們現在大概已經到北京了吧？

—Ought I to go? 我該去嗎?

—Yes, you ought (to). 對，你該去。

5. ought to與 should的用法區別

一般說來，二者可替換，只是ought to語氣稍重些。如：

He ought to / should have arrived long ago. 他早就該到了。

You should / ought to have come yesterday. 你應該昨天來的。

(1) 表示因責任、義務等或表示出于法令規則、行為準則、道德責任等客觀情況該做的事時，常用ought to； should則含有個人意見，強調主觀看法。如：

You are his parents. You ought to take care of him. 你們是他的父母，應當管他。

They oughtn’t to let their dog run on the road. 他們不該把狗放出來滿街跑。

Such things ought not to be allowed. 這類事不該允許。

(2) 在公告、須知或條例中，出于禮貌，常用should：

You should not run alongside the swimming-pool. 不準在游泳池邊奔跑。