Identify the direct object.

The baseball pitcher threw his teammate on first base the ball.

pitcher
teammate
first base
ball

ball

The direct object in the sentence is "ball."

To identify the direct object in a sentence, follow these steps:

1. Determine the subject of the sentence: In this case, the subject is "the baseball pitcher."

2. Identify the verb: The verb in this sentence is "threw."

3. Ask the question "Who or what was thrown?" This will help you identify the direct object of the sentence.

In the given sentence, the direct object is "the ball" because it is the receiver of the action of the verb "threw." The ball is what the pitcher threw. Therefore, the direct object in this sentence is "ball."