Adverb:
An adverb is a word that modifies or describes a verb, adjective, or other adverb. It provides information about how, when, where, or to what extent an action is performed.

Identifying the Adverb:
To identify the adverb in the given sentence "We should now begin our homework," we need to understand the function of each word and determine which word modifies the verb "begin."

- "We" is a pronoun that refers to a group of people.
- "Should" is a modal verb indicating obligation or advisability.
- "Now" is an adverb that indicates the time of the action.
- "Begin" is the verb that expresses the action of starting something.
- "Our" is a possessive adjective showing ownership.
- "Homework" is a noun referring to the task assigned to be completed outside of school.

The Adverb:
In this sentence, the adverb is "now." It modifies the verb "begin" by providing information about when the action should take place. It indicates that the action of beginning the homework should happen at the present time.

Explanation:
The sentence "We should now begin our homework" suggests that it is the appropriate time to start doing the assigned homework. The adverb "now" adds a sense of immediacy or urgency to the action. It indicates that the speaker believes the task should be started promptly.

The adverb "now" answers the question "When should we begin our homework?" and provides the timing or moment for the action. It helps to convey the speaker's intention of starting the task without delay.

In summary, the adverb "now" in the sentence modifies the verb "begin" and indicates the specific time or moment when the action of starting the homework should occur.