Put the verb in brackets in the correct form:

The girl (do) her homework now.

The girl is doing her homework now.

Explanation:
- The given sentence is in the present continuous tense, which is used to express an action that is happening at the moment of speaking or around the current time.
- In this case, the action is "doing her homework."
- To form the present continuous tense, we use the helping verb "is" with the subject "girl" and add the base form of the main verb, which is "do."
- The base form of the verb "do" remains the same; it doesn't change for the third-person singular subject (girl) in the present continuous tense.