Many teenagers_______ the old and they often offer their seats to the old on buses.
—Which university do you want to enter?—It’s hard for me a decision.
He is __________ unusual inventor and he invented _________ useful invention.A. a; an B. a; a C. an; an D, an; a
I didn’t know __________. Can you tell me?
It’s very kind _________ you to help me carry the boxes since it is difficult _________ a person like you to carry so heavy things.
____ of the students has finished the exam, so ___ has come out of the classroom.