--- I rang you at about nine, but there was no reply.--- Oh, that was probably _______I was seeing the doctor.
They suggested that the library ________ open during the vacation.
If I can help________, I don’t like to working late into the night.
Only by _______ your attention _______ what you are learning can you learn it well.
—Do you mind if I smoke here? — ___________.
It’s not _________ good idea to drive for four hours without _______ break.