Select the most appropriate option that can substitute the underlined segment in the given sentence.
Peter was the last to know that she had been cheating of him.
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. cheating on him.
The correct phrase is "cheating on him" because "cheat on" is the standard idiomatic expression used to describe being unfaithful in a relationship.
In this context, "on" specifically refers to one person being unfaithful to another.
The other options are incorrect.