Unit 12.1

Modals Could and Need in the Past

Modal Verbs

Present perfect of modal verbs refer things that did not take place in past.

We also use them to talk about possibilities and to describe that something was different in the past.

The formation of modals could and need in the past is:

  • The structure for could have + past participle is:
    Subject + could + have + past participle + …
  • The structure for couldn’t have + past participle is:
    Subject + could + not + have + past participle + …
  • The structure for need + not + have + past participle is:
    Subject + need + not + have + past participle + …
  • You could have bought a bouquet of flowers but you didn’t.
  • They couldn’t have done anything for drought.
  • You needn’t have fed the marine animals in the ocean.

There are some differences between modals in the past:

  • We use Could + have + past participle to talk about past actions that we didn’t carry out even if we were able to ;
  • We use Couldn’t have + past participle to talk about actions that were impossible to do, even if we wanted to do them;
  • We use Needn’t have + past participle to talk about actions that happened in the past, which were unnecessary or waste of time.

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