—I lost my pet pig, but it came back yesterday.—As the saying goes: an old horse knew the way.

 As to the question of whether we will sell our house or who we shall sell the house to, you ____ have answer by tomorrow.

 —Look! A book is on the floor. Whose is it?—It ______be Rick's. It has his name on it.

Why______ you do everything as if you have to win?

Teachers _______ be sensitive to the development level of each student so as to help them better.