What is the simple subject of the following sentence? I am thinking it is "part," but it also seems like it could be "park."

A large part of the park is under water.

You're right. The simple subject is "part."

The simple subject can't be "park" because "park" is the object of a preposition.

Also -- the park isn't under water -- only a part of it is submerged.

The simple subject of the sentence "A large part of the park is under water" is "part."

To determine the simple subject of a sentence, you need to identify the main noun or pronoun that the sentence is mainly about. In the given sentence, "A large part of the park is under water," you are correct that "part" is the simple subject.

Here's how you can find the simple subject:

1. Identify the subject: The subject in this sentence is "a large part of the park." It represents the main noun phrase that the sentence is focused on.

2. Simplify the subject: Remove any modifying words or phrases to simplify the subject. In this case, you can eliminate "a large" because it only describes the size of the part. So, we are left with "part of the park."

3. Determine the main noun: The main noun in the simplified subject is "part."

Therefore, the simple subject of the sentence is indeed "part."