___ most of the earth’s surface is covered by water, fresh water is very rare and precious

We are sure the_________Olympic Games in Beijing next year will beone of_________games in history.

The woman told the workers that her house _____.

It was thequality of life in the future Itook this training course，not just to make more money

(2010·上海)Wind power is an ancient source of energy ________ we may return in the near future