Wehave to keep _______ with the changing times.

Can I get my ears pierced, Mom —No. As a student,you ________ do that.

Must I stay here with you—No, you_____. You may go home, but you ______ go to the net bar.

Seen from space, the earth looks like a blue ball, with __________ 75% of its surface covered with water [ ]

29. The teachers are said to have moved to that ______ building, where they can work and live better than before.