2705.What percentage of water on the earth can be directly used by us?( ?。?br />
This may seem strange to you because nearly 75% of the earth's surface is covered with water.But about 97% of this water is sea water.We can only drink and use the other 3% of the fresh water that comes from rivers,lakes,and other sources.And we cannot even use all of that directly,because some of it is in the form of icebergs and glaciers.
2708.Mr.Green has a family.If he buys the house,he will ________.( ?。?br />
HOUSE FOR SALE Comfortable family home with a large garden on north side of town.Three bedrooms,living-room,kitchen,dining-room,bathroom.Offers over 550,000.