The girl was often heard ______ happily in her room.
| A．sing | B．to sing | C．singing | D．sings |
____ do you spell "photo"?
A. What B. How C. Who
— Are these your books?
—No, they aren't. They're____.
A. her B. his C. mine
—Is he your father, Kate?
—Yes,_____.
A. he's B. he is C. she is
Those boys are my ______.
A. brothers B. brother C. sisters
—What's your QQ number?
—______ 54863.
A. It B. It's C. Its