Takes or take, subject verb agreement

Question

1. Veronica takes a lot of time.

2. Let Veronica take her time.

Could you guys help me with the grammar rule involved while deciding why we'll use the verb 'take' and not 'takes' in the second sentence?

Answer 1

Take here is not plural: it is the base form of the verb (sometimes called the infinitive).

Finite verb forms like takes (and, for that matter am, is, are) are only used when they are the main verb of the clause.

When they are governed by another verb (whether a modal like can and should, an auxiliary like be, have and do, or one of the harder to classify examples like let and make and have to) they take another form.

In nearly all cases that form is always the base, or infinitive - which for every verb except be happens to be the same as the plural form.

So

Veronica takes a lot of time.

but

Veronica may take a lot of time.

Veronica shouldn't take a lot of time.

Veronica needs to take a lot of time.

Let Veronica take a lot of time.

And for completeness, the exceptions I mentioned:

Veronica has taken a lot of time. (Present perfect)

Veronica is taking a lot of time. (Continuous)

Veronica is taken to the theatre by her aunt. (Passive)

Veronica gets taken to the theatre by her aunt. (Colloquial passive)