Past modals for advice and obligation

Use should have, need not have and was supposed to when evaluating past choices and expectations.

When do we use it?

Distinguish criticism, unnecessary completed action and an unmet arrangement.

Form

Should have = better past choice; needn’t have = unnecessary action done; was supposed to = expected action.

• You should have called.
• We needn’t have rushed.
• He was supposed to arrive at six.

Key contrast

At B2, choose the form from the complete context: sequence, viewpoint, degree of certainty and clause structure all matter.

Common mistakes

• You should called. → You should have called.
• We didn’t need have rushed. → We needn’t have rushed.

Remember

Use should have, need not have and was supposed to when evaluating past choices and expectations.

Quick check

• Identify the time relationship or intended meaning.
• Check the auxiliary, participle and clause pattern.
• Eliminate answers that fit the words but not the context.