Mary_______ not ride a bike in the past,but now she_______ do it.

Whydidn’tyou go to play football with us yesterday afternoon? —I_____my mother with the housework then.

—Got your driving license?—No. I ________ too busy to have enough practice, so I didn’t take the driving test last week.[ ]

________ energy is generated from natural resources—such as sunlight, wind, rain, tides and so on.

____________I take the book out?—I’m afraid not.