We kept watching the house in the garden until the lights of the house ______.

_______ did you stay in America— For about two weeks.

To save animals is in danger, people decide to more nature parks.

chnology of electronic products is________changing, so you needn’t follow the fashion

15．– How cold it is! I wonder how grass survive under such heavy snow． –Don’t worry．There is a lot of air in loose snow which _______．