- English Grammar B2 Level - https://open.books4languages.com/english-b2-grammar -

Modals Could and Need in the Past

Introduction

Present perfect [1] of modal verbs refers to things that did not take place in the past.

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

Form

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 + …

Example

  • You could have bought a bouquet of flowers but you didn’t.
  • He could have made a plan for the trip, but he didn’t.
  • couldn’t have used my camera, cause its not working anymore.
  • They couldn’t have done anything for drought.
  • She needn’t have read the plot before coming to the play.
  • You needn’t have fed the marine animals in the ocean.

Use

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 a waste of time.

Summary

The modal verbs could and need in the past are used to talk about possibilities and to describe that something was different in the past.

More specifically:

  1. We use could have with the past participle to talk about past actions that we didn’t carry out even if we were able to;
  2. We use couldn’t have with the past participle to talk about actions that were impossible to do, even if we wanted to do them;
  3. We use needn’t have with the past participle to talk about actions that happened in the past, which were unnecessary or a waste of time.

Their structure in the past is:

  1. We start with the subject of the sentence followed by could have, the past participle form of the verb and the rest of the sentence;
  2. We start with the subject of the sentence followed by could not have, the past participle form of the verb and the rest of the sentence;
  3. We start with the subject of the sentence followed by need not have, the past participle form of the verb and the rest of the sentence.

For example:
— “He could have said goodbye before he left but he didn’t.” = He didn’t say goodbye even though he was able to.
— “We couldn’t have visited you last week, beacause there were no flights available.” = It was impossible to visit you last week, even if we wanted to.
— You needn’t have cooked that much food at the birthday party, as we weren’t that many pleople.” = It was unnecessary to cook that much food, but they did.

Let’s revise this content within the {Form} section. Take a look at the {Example} section that shows its use within a context.