Can some one tell me if my examples are correct or if I need to do them over?

Adjectival prepositional phrase:
I like playing basketball at the gym every other weekend.

Post noun modifier:
I like the sun when it is bright and hot in July.

Participial Phrase:
I dislike buying an item at the store to find a damaged item when opened.

Adjective clause:
I dislike watching baseball games, which are not even close in scoring.

Adjectival prepositional phrase:

I like playing basketball at the gym every other weekend. If you mean "at the gym" that's incorrect -- it's being used adverbially (telling where).

Post noun modifier:
I like the sun when it is bright and hot in July. Looks good.

Participial Phrase:
I dislike buying an item at the store to find a damaged item when opened.
Which words make up the prepositional phrase?

Adjective clause:
I dislike watching baseball games, which are not even close in scoring.
Looks OK.

Adjectival prepositonal phrase:

I like in our house the big kitchen to cook in. (in our house is the adjectival prepositonal phrase)

Participal Phrase:
I dislike ordering an item online to find a damaged package when it arrives. (damaged package is the participal phrase)

To determine if your examples for different grammatical structures are correct or need revision, we can analyze them individually:

1. Adjectival prepositional phrase:
Your example, "I like playing basketball at the gym every other weekend," contains an adjectival prepositional phrase ("at the gym"), which modifies the noun "basketball." This phrase functions correctly, providing additional information about where you enjoy playing basketball. Thus, your example seems correct.

2. Post noun modifier:
Your example, "I like the sun when it is bright and hot in July," features a post noun modifier ("when it is bright and hot in July") that describes the noun "sun." This construction is appropriate because it adds further detail about your preference for the sun specifically during July. Hence, your example appears to be correct.

3. Participial phrase:
In your example, "I dislike buying an item at the store to find a damaged item when opened," you've used a participial phrase ("buying an item at the store") to describe the noun "dislike." However, there seems to be an error in parallel structure since the second part of the phrase ("to find a damaged item when opened") does not match the form of the first part. To revise this, you could consider saying, "I dislike buying items at the store only to discover they are damaged when opened." This revised version maintains parallelism and clarity.

4. Adjective clause:
Your example, "I dislike watching baseball games, which are not even close in scoring," includes an adjective clause ("which are not even close in scoring") modifying the noun "games." This construction seems appropriate, providing additional information about why you dislike watching baseball games. Therefore, your example appears to be correct.

In summary, your examples for the adjectival prepositional phrase and post noun modifier seem correct. However, the participial phrase could benefit from revision for better parallel structure, and some adjustment would improve the clarity and grammar within the adjective clause.