45. A. faster                  B. farther                  C. closer                D. lower

A

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!