In English grammar, noun phrases that include relative clauses play a significant role. They employ relative pronouns such as “that” or “who” to link two thoughts in a single sentence.

Consider the following examples where the use of relative pronouns “that” or “who” is optional:

• “I’d be worried about something, specifically the local food.” / “The local food is a thing about which I’d be worried.”

• “There’s one thing I’d really miss, hanging out with my friends.” / “One thing I’d miss is the experience of hanging out with my friends.”

• “The individuals I’d miss the most are my parents.” / “My parents are the individuals whom I’d miss the most.”

These structures provide a concise way for English speakers to express intricate ideas. The choice to use “that” or “who” is discretionary in these instances.