Introductory notes about using modals to talk about the past
Lots of students find using modals to talk about the past daunting and difficult to comprehend. Despite the partial truthfulness of this claim, it is not impossible to understand the nuances of the uses of modals. In this lesson, I will attempt to make things as easy as possible. So with little concentration, you will be able to use modals correctly.
Generally speaking, we use modal+verb to refer to a present situation or an action that takes place in the present time. But we use modal+have+past participle to refer to a past situation or an action that happened in the past but couldn’t be changed. These modals, especially “should have“, could have“, and “would have” are often called modals of “lost opportunity” because the possibility to change the past situation or event is no longer available.
Some models are used to talk about the past not by adding “have+past participle”, but by changing their forms. the good examples that can be mentioned in this respect are “had to“, “didn’t have to“, “didn’t need to“, and “could“.
Using modals in the past can, in some cases, be tricky and challenging. To help you with this issue, I have tried to gather all their uses in the following table, along with illustrative examples and their meanings.
Modal | Function | Example | Meaning |
Had to | Past obligation | I had to take the pills for three days. | I was obliged to take the pills for three days. |
Must | Positive certainty /deduction/conclusion | They must have disappeared. | I am sure that they disappeared. |
Can’t | Negative certainty | She can’t have stayed in the hospital for more than two days. | I am sure she didn’t stay in the hospital for more than two days. |
Needn’t | Lack/absence of obligation/ necessity | I needn’t have gone to the doctor. | It wasn’t necessary for me to go to see a doctor. |
didn’t have to | Lack/absence of obligation/ necessity | I didn’t have to go to see a doctor. | It wasn’t necessary for me to go to see a doctor. |
didn’t need to | Lack/absence of obligation/ necessity | I didn’t need to go to the doctor. | It wasn’t necessary for me to go to see a doctor. |
Should | Positive advice/advisability | He should have made more effort. | It was advisable for him to make more effort (but he didn’t). |
Shouldn’t | Negative advice/advisability | He shouldn’t have done that. | It was advisable for him not to do that (but he did). |
Could | Past ability/capability | When I was younger, I could go upstairs quite easily. | When I was younger, I was able to go upstairs quite easily. |
Couldn’t | Past prohibition | In the past, people couldn’t express themselves freely. | In the past, people weren’t allowed to express themselves freely. |
Could | Past possibility | They could have talked to him about the issue. | I think they talked to him about the issue. |
May | Past possibility | They may have talked to him about the issue. | I think they talked to him about the issue. |
might | Past possibility | They might have talked to him about the issue. | I think they talked to him about the issue. |
Remarks
- Had to+verb = Was/were obliged to
- Must have+past participle = I am sure something was done
- Can’t have+past participle = I am sure something wasn’t done
- Couldn’t+verb = wasn’t/weren’t able to.
- Couldn’t +verb = wasn’t/weren’t allowed/permitted
- Could have+past participle = I think something was done
- Couldn’t have+past participle + I think something wasn’t done
- May have+past participle = I think something was done
- May not have+past participle = I think something wasn’t done
- Might have+past participle = I think something was done
- Might not have+past participle = I think something wasn’t done
- Should have+past participle = It was advisable
- Shouldn’t have+past participle = It wasn’t advisable
- Needn’t have+past participle = It wasn’t necessary
- Didn’t have to+verb = It wasn’t necessary
- Didn’t need to+verb = It wasn’t necessary
Exercise
Fill in the blanks in the following sentences with the correct modal to express the functions between brackets.
- Nadia ………………….. have left her bag on the bus. (express certainty)
- Five years ago, I ……………… read and write. (express ability)
- Kate ……………………. drive when he was thirteen years old. (express ability)
- Immigrants ..…………take a lot of money with them to their home country. (express prohibition)
- Paul and his brother………………….have considered a career in the armed forces. (give advice)
- I ……………………. have phoned Julie that night. (express absence of obligation)
- Laura ……………………. to go to the dentist last Friday, because she had a terrible toothache. (express obligation/necessity)
- You …………………. have done Exercise D. It was optional. (express absence of obligation)
- Andrew ………….. work a lot harder if wanted to get a good report. (express obligation/necessity)
- Jane and Alain .. ………………… have arrived at about 8:00 a.m. (express probability/possibility)
- Sean ……………… have been caught in the traffic. (express certainty/deduction)
- You ……………………. have worried so much about Jane’s absence. (express lack of obligation/necessity)
- They …………. not find a hotel room so they had to sleep in the car. It was awful. (express ability)
- Catherina ……………… pay for the tickets as her husband paid for them. (express absence of obligation)
- Students …..………….. not connect to the internet before you came and fixed it. (express ability)
- I ………….. have gone to the concert early. All the tickets had sold out before my arrival. (express positive advice)
- I …………… have cheated in the exam. (express negative advice)
- Fiona …………… have forgotten the meeting. I reminded her this morning. (express negative certainty/deduction)
- George ………….. have left his bag in the garage. (express positive certainty/deduction)
- The situation ………………….. have worsened. (express possibility)