What do you think of Tom？–He is a man of______words. He always stays alone(独自地).

Let’s go hiking _____ staying at home, shall we?—A good idea. [ ]

Have you heard _____ your father? — Not yet. [ ]

____ UFO landed on Center Park and ______ alien got out of _______ UFO.

Must we keep the window _______ all the time? —No, you don’t have to.