In this reference, we will discuss the role of modal verbs in the perfect infinitive, the types of modals used with it, common mistakes to avoid, and advanced uses of the perfect infinitive with modals. Let’s get started!

Perfect Infinitive with Modals

An infinitive is simply a verb form that's not conjugated. In English, it is usually preceded by ‘to’ and is used in many situations. For example, ‘I want to go to the store’ or ‘I need to study for my exam’.

The perfect infinitive is a type of infinitive that is used to express an action that has happened in the past. You can form it by combining the auxiliary verb ‘have’ with the past participle of the verb. For example, the perfect infinitive of the verb ‘go’ is ‘to have gone’.

Modals are auxiliary verbs that are used to express various meanings such as ability, permission, obligation, and so on. They can be used in combination with a perfect infinitive to express an action that has happened in the past.

The Role of Modals in Perfect Infinitive

Modals play an important role in the perfect infinitive. They are used to express the meaning of the perfect infinitive more clearly and accurately. For example, the perfect infinitive ‘to have gone’ can be used to express an action that has happened in the past.

However, when combined with the modal ‘must’, it becomes ‘must have gone’, which expresses that the action was necessary or obligatory.

Similarly, when combined with the modal ‘can’, the perfect infinitive ‘to have gone’ becomes ‘can have gone’, which expresses that the action was possible or allowed.

Types of Modals Used with Perfect Infinitive

There are many types of modals that can be used in combination with a perfect infinitive. The most common modals are ‘must’, ‘can’, ‘could’, ‘may’, ‘might’, ‘should’, ‘would’, ‘shall’, and ‘ought to’. Each of these modals has a different meaning and can be used to express different ideas.

Here are some examples:

• ‘must’ helps express obligation or necessity.
• ‘can’ helps express possibility or permission.
• ‘could’ helps express possibility in the past.
• ‘may’ helps express permission in the present or future.
• ‘might’ helps express possibility in the present or future.
• ‘should’ helps express advice or recommendation.
• ‘would’ helps express preference or desire.
• ‘shall’ helps express future plans or intentions.
• ‘ought to’ helps express moral obligation.

As you can see, all of these auxiliary verbs can work with the perfect infinitive quite well.

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Examples of Perfect Infinitive with Modals

Now that you know the types of modals used with it, let’s look at some examples.

“You must have gone to the store by now.”

‘to have gone’ combined with the modal ‘must’ becomes ‘must have gone’. This expresses that the action was necessary or obligatory.

“You could have gone to the store yesterday.”

‘to have gone’ combined with the modal ‘could’ becomes ‘could have gone’. This expresses that the action was possible in the past.

“You may have gone to the store today.”

‘to have gone’ combined with the modal ‘may’ becomes ‘may have gone’. This expresses that the action is possible in the present or future.

“You should have gone to the store yesterday.”

‘to have gone’ combined with the modal ‘should’ becomes ‘should have gone’. This expresses that the action is advisable or recommended.

“You would have gone to the store if you had the time.”

‘to have gone’ combined with the modal ‘would’ becomes ‘would have gone’. This expresses that the action is desired or preferred.

“You shall have gone to the store by tomorrow.”

‘to have gone’ combined with the modal ‘shall’ becomes ‘shall have gone’. This expresses that the action is planned or intended.

“You ought to have gone to the store yesterday.”

‘to have gone’ combined with the modal ‘ought to’ becomes ‘ought to have gone’. This expresses that the action is obligatory. 
 
 

Uses of Perfect Infinitive with Modals

The perfect infinitive with modals can help you talk about a past action that was necessary, possible, advisable, desired, planned, or morally obligatory. It can also help you talk about an action that was not done but could have been done.

For example, “You should have gone to the store yesterday.” This expresses that the action of going to the store was advisable or recommended.

The perfect infinitive with modals can also be used to make polite requests or to give advice. In the sentence “You could have gone to the store if you wanted.” This expresses that the action of going to the store was possible and is being suggested as a polite request.

Common Mistakes to Avoid in Perfect Infinitive with Modals

When using perfect infinitive with modals, it is important to make sure that the correct modal is used. For example, the modal ‘can’ is used to express possibility or permission, while the modal ‘could’ helps express possibility in the past.

Make sure that the verb form is correct. For example, the perfect infinitive of the verb ‘go’ is ‘to have gone’, not ‘to had gone’.

Also check the tense of your verb. For example, when using the modal ‘should’, the perfect infinitive should be used to express a past action, not a present action.

Advanced Uses of Perfect Infinitive with Modals

In addition to the uses we discussed above, perfect infinitive with modals can also be used to express regret or apology. For example, “I should have gone to the store yesterday.”

This expresses that the speaker regrets not going to the store.

It can also be used to make a suggestion or offer. In the sentence “You could have gone to the store if you wanted.” This expresses that the speaker is suggesting or offering the action of going to the store.

You can also use perfect infinitive with modals to express a wish or desire. You could say “I wish I had gone to the store yesterday.” This expresses that the speaker wishes they had gone to the store.

Summary

In this reference, we discussed the role of modals in perfect infinitive, the types of modals used with it to create fun and engaging sentences. From now on, you should be able to use it correctly in your writing and speaking.

If you want to learn more about perfect infinitive and other aspects of English grammar, see more handy references below!