291. In asking permission, the proper form is “May I?” not “Can I?” With negatives, however, can is more common than may, except in questions. Thus,—
- Question. May I (or mayn’t I) play ball this morning?
- Answer. No, you cannot; but you may play this afternoon.
292. Must expresses necessity or obligation.
- We must all die sometime.
- You must wait for the train.
- You must not be discouraged by failure.
Note. Must, though originally a past tense, is in modern English almost always used as a present. Past necessity may be expressed by had to with the infinitive: as,—“I had to wait for the train.”
293. Ought with the present infinitive, expresses a present duty or moral obligation; with the perfect infinitive, a past duty or obligation. Should is often used in the same sense.
- I ought to write that letter. [Present.]
- You ought not to object. [Present.]
- This roof ought to be mended. [Present.]
- I ought to have known better. [Past.]
- Your dog ought not to have been unleashed. [Past.]
- You should be careful. [Present.]
- The garden should have been weeded yesterday. [Past.]
Note. Ought is really an old past tense of the verb owe, but is now always a present. Its former meaning may be seen in Dame Quickly’s “You ought him a thousand pound” (Shakspere, 1 Henry IV, iii. 3. 152).
Had should never be prefixed to ought.
| Correct | Incorrect |
|---|---|
| You ought to stay at home. | You had ought to stay at home. |
| We oughtn’t to make so much noise. | We hadn’t ought to make so much noise. |
| John ought to begin, oughtn’t he? | John ought to begin, hadn’t he? |