Whose shirt is this? Is it Tom’s? — No, it isn’t. _______ is white.

Who taught ________ to write the computer program?—Nobody. She learned it by __________.

I do my homework _____ ten o’clock every night.[ ]

Miss Lin____________ a lot of work for the poor area since 2010.

Some researchers believe that there is no doubt ______a cure for AIDS will be found.