--Would you please explain to me about the difference between the two phenomenon? --I’m sorry, but that’s just _____ I’m puzzled about.
The man ____ you talked just now is a worker.
The man ____ you are going to make friends is my father’s neighbour.
The doctor ____ is leaving for Africa next month.
The man ____ around our school is from America.
He talked about a hero ____ no one had ever heard.