4.219 importance: 'should' and 'ought to'

'Should' and 'ought to' are used in three different ways when you are talking about the importance of doing something.

You use 'should' or 'ought to' when you are trying to help someone by advising them to do something.

• Carbon steel knives should be wiped clean after use.
• You should claim your pension 3-4 months before you retire.
• You ought to try a different approach.

You use 'should' or 'ought to' when you are saying that something is the right or correct thing to do.

• We should send her a postcard from Eastbourne.
• Whoever discovers the body should contact the family doctor.
• We ought to stay with him.
• You ought not to do that.

You use 'should' or 'ought to' with 'have' and a past participle to say that something was desirable in the past, although it did not in fact happen.

• One sailor should have been asleep and one on watch.
• We ought to have stayed in tonight.
• A more junior member of staff ought to have done the work.

You also use 'should' and 'ought to' to say that you expect something to happen. This use is explained in paragraph 4.136.