Identify the phrase contained in the following sentence.

Choose your words with great care.

participle

gerund

infinitive

preposition

Choose your words with great care.

I think the above sentence is infinitive.

An infinitive will almost always begin with "to" followed by a simple form of verb. There are also sentences where "to" is missing but implied.

In the above sentence, "to" is missing but it is implied.

"Choose your words with great care" can be "to choose your words with great care"