The Issue:
* "Of companies" is a prepositional phrase and doesn't act as a subject.
* "Its" is singular possessive, but "companies" is plural.
Corrections:
You need to change the sentence structure to make it grammatically correct. Here are a few options:
1. "A number of companies gave their employees a..." This uses a plural subject ("companies") and the correct plural possessive ("their").
2. "The company gave its employees a..." This focuses on one specific company, using the singular subject "company" and the singular possessive "its".
3. "Some companies gave their employees a..." This is another way to make the subject plural and use the correct possessive.
Example:
* Incorrect: Of companies gave its employees a raise.
* Correct: A number of companies gave their employees a raise.
Choose the option that best fits the context and meaning you're trying to convey.