How does he usually spend his weekends—He spends as much time as he can _______ computer games .

pace, the earth looks blue. This is about seventy-one percent of its surface is covered by water.

Some scientists think there are _______ 2，000 million flashes oflightning per year.

What if I can’t finish my task today–______.You still have another week left.

If Newton lived today, he would be surprised by what in science and technology.[ ]