Question

we must do it (use infiniteve)​

Answer 1

The infinitive form of this sentence will be:

I have to do it now.

If we know the rule we can easily solve the question. by looking at the sentence we can tell it is infinitive or not.

RULE: to+ verb first form = infinitive sentence

Make infinitive the subject or the object of the sentence and use infinitive form of verb as normal verb but as a noun.

For example: " She likes to run." The infinitive form in this is "to run" is the object of the verb "she likes".

Answer 2

Explanation:

You can also use the infinitive to show your intention, after a verb that involves saying something. Verbs such as “agree”, “promise” and “decide” can all use the infinitive form. E.g. “She agreed to share the money between them.” E.g. “He decided to change schools.