______ you study hard, you will pass the exam.

_____ are manatees?—They are about 10 feet long and weigh about 1, 000 pounds. [ ]

Do you know the boy ___ is standing under the tree?– Yes, he is my friend, Peter.

Let me teach ____ daughter Japanese.–Thanks. If so, she won’t have to learn by ____.

__________ did the silk dress ________ you ? —150 yuan.[ ]