* Direct objects receive the action of the verb.
* Ask "What?" or "Whom?" after the verb.
Examples:
* "She gave us a gift."
* The verb is "gave".
* "What?" She gave *us* a gift. ("Us" receives the gift)
* "Us" is the direct object.
* "They invited us to the party."
* The verb is "invited".
* "Whom?" They invited *us* to the party. ("Us" receives the invitation)
* "Us" is the direct object.
However, "us" can also be a part of a prepositional phrase, which is NOT a direct object:
* "He talked to us about the plan."
* The verb is "talked".
* "Whom?" He talked *to us* about the plan. ("Us" is part of the prepositional phrase "to us")
* "Us" is NOT the direct object.
So, to determine if "us" is a direct object, you need to look at the entire sentence and figure out the verb and what "us" is directly receiving.