The verb “to have” is very versatile. It forms the perfect tenses and also has its own meaning which shows possession. For example:
- I have a cat.
As a semi-modal verb
When “to have” is in the form “have to”, it functions like must, showing obligation and is a semi-modal verb.
But why is it a semi-modal verb and not a modal verb? The reason is a simple one: a modal verb is a single word that functions as a verb. However it is (technically) a verb and a preposition that functions as a modal verb. Because it is multiple words, it is a semi-modal verb (modal verbs are only one word).
Some examples as a semi-modal verb include:
- We have to attend class to improve our knowledge of English.
This example shows the requirement to attend class.
What about the past?
The past tense of “have to” follows the verb “to have”, namely “had to”. For example:
Present: We have to attend class to improve our knowledge of English.
Past: We had to attend class to improve our knowledge of English.
Seems simple right? But is there anything special about the past tense?
The answer is yes! A previous post spoke about the modal verb “must” but if you are trying to use the sense of must in the past tense, you must use “had to” unless you are speculating about something (in that case, you use “must have”). For example:
Present: I must go home. / I have to go home.
Past: I had to go home.
While “must” and “have to” often seem interchangeable in the present, the only possibility in the past is “had to”.
What is/are the difference(s) between “must” and “have to”?
I am glad that you asked! This question is covered by another post, entitled “must vs have to”.
Want to learn more about modal verbs? Here is a guide to all the semi-modal verbs: introduction to semi-modal verbs. You can also learn more about other English language information on my Teaching English page.