—Listen! Someone is singing in the next room. Who ____ it be? Is it Li Wei?—No, it ______ be her. She is at school now.
At the foot of the hill you could hear nothing but the ______ of the running water.
—Must I finish the exercise this afternoon? —Yes, you ______, but you ______ finish it now.
J K Rowling jumps farther than ______ in her class.
English is ______ used than Chinese in the world.
His father looks young, but in fact he is ______.