* Missing Preposition: You need a preposition like "to" or "at" to show the relationship between "went" and "the park".
Here's how to fix it:
* "I and Liza went to the park."
* "I and Liza went at the park." (This is less common but still grammatically correct depending on the context.)
Important Note: While grammatically correct, "I and Liza" sounds a bit awkward. It's more natural to put the other person first:
* "Liza and I went to the park."