The world is not only hungry,it will also be thirsty for water.About 97% of water on the earth is sea water,or salty(咸的)

The world is not only hungry,it will also be thirsty for water.About 97% of water on the earth is sea water,or salty(咸的) water.Man can only drink or use the other 3% of the fresh water(淡水) which comes from rivers,lakes and underground.
　　The sea is very big.Look at the map of the world,there is more sea than land.It covers(覆盖) quarters of the earth,it looks very beautiful when the sun is shinning on it.but it can be terrible when there is a strong wind.
　　Some parts of the sea are very deep.There is one place near Japan.It's nearly 11 kilometers high.If we put that mountain into the sea at that place,there would be 2 kilometers of water above it!
　　The sea is salty.There is one "sea" called the Dead Sea.The Dead Sea is not a sea.It's a big lake in the Jordan Valley.It's the saltiest.It's near the city of Jericho.It's about 80.kilometres long,between 4.8 and 17.7 kilometers wide.The river Jordan runs into the Dead Sea.The sun is not there and the water is salty.Fish can't live in the Dead Sea and plants can't grow near it.People can't swim well in the Dead Sea,but they can't float(漂浮) on the water.The water is very blue and the air is clean.In winter people come to the Dead Sea to enjoy the sunshine.
46.Does the fresh water come from rivers,lakes and underground?
　　A.Yes,it does.B.No,it doesn't.C.Yes,it doesn't.D.No,it does.
47.The deepest place in the sea is near .
　　A.Japan B.India C.America D.China
48.The passage tells us the sea covers of the earth.
　　A.3% B.25% C.75% D.97%
49.The Dead Sea is .
　　A.80 kilometers long B.2 kilometers wide
　　C.11 kilometers deep D.17.7 kilometers high
50.According to the passage,which of the following isn't true?
　　A.The river Jordan run into the Dead Sea.
　　B.The world will be thirsty for water.
　　C.The sea looks beautiful when the sun-is shining on it.
　　D.The Dead Sea is the saltiest sea in the world.