Explanation:

Subject Pronouns:
In English grammar, subject pronouns are used to replace a noun that is the subject of a sentence. They are commonly used to avoid repetition and make sentences more concise. Some examples of subject pronouns are "I," "you," "he," "she," "it," "we," and "they."

Identifying the Subject Pronoun:
To identify the subject pronoun in the given sentence, we need to determine the noun that the pronoun is replacing. In this case, the noun being replaced is "Simon." The subject pronoun that replaces "Simon" is "he."

Explanation of the Answer:
The correct answer to complete the sentence "On the left you can see Simon. _____________is my brother" is "He." Here's the breakdown of why "He" is the correct answer:

1. The sentence is introducing Simon as the person on the left.
2. Since Simon is the subject of the sentence, a subject pronoun is used to replace his name to avoid repetition.
3. The subject pronoun that refers to Simon is "he," which is the correct answer to complete the sentence.

Example Sentence with the Correct Answer:
The completed sentence would be: "On the left you can see Simon. He is my brother."

Summary:
In English grammar, subject pronouns are used to replace nouns that are the subjects of sentences. In this case, "He" is the correct subject pronoun to replace the noun "Simon" in the given sentence. Using subject pronouns helps to avoid repetition and make sentences more concise.