—Do you know the boy _______ is talking to Mr. Smith?—Yes, he's my brother.A. what B. which C. Who
Thomas Edison is known _____inventions______ a great inventor.
An accident______ on this road last week.
Tom is often made ______for twelve hours a day by the boss.
I don’ t mind _____the door.
There are some dangerous fish in the river, and I’ve warned Jack______ here.