Although he is very old, ______ he works very hard
I have made ________ new friends here that I really enjoy my school life.
—Do you know ________ Simon is?—I met him in the school library just now. He may be still there.
It’s too cold outside. I prefer staying at home ________ on such a day.
It is raining ________ outside. You’d better not leave now.
They were made ________ from time to time because Tom told many jokes.