填空题

What We Take from and Give to the Sea
As long as we have been on earth, we have used the sea around us. We take from the ocean, and we give to it.
We take fishes from the ocean millions of kilograms of fish, every year, to feed millions of people. (46) . We take minerals from the ocean. One way to get salt is to place seawater in a shallow basin and leave it until it evaporates. (47) . Much gold and silver drift dissolved in the waters of the sea, too. But the sea does not give them up by simple evaporation. Other gifts from the sea are pearls, sponges and seaweed. Pearls become jewelry. (48) . Seaweed becomes food of many kinds--even candy, and ice cream as well as medicine. Believe it or not, fresh water is another gift from the se

• a. We cannot drink ocean water. (49) . But ocean water becomes fresh water when the salts are removed. In the future, we will find ourselves depending more and more on fresh water from the sea.
  The sea gives us food, fertilizer, minerals, water, and other gifts. What do we give the sea Garbage. (50) . Huge as it is, the ocean cannot hold all the water that we pour into it. Dumping garbage into the ocean is killing off sea life. Yet as, the world population grows, we may need the sea and its gifts more than ever.
  We are finally learning that if we destroy our seas, we might also destroy ourselves. Hopefully, it is not too late.A. Natural sponges become cleaning aids.B. We pollute the ocean when we use it as a garbage dump.C. The area of the sea is becoming smaller and smaller.D. Along with salt, other minerals were left after evaporation.E. We even use their bones for fertilizer.F. Some of its contents may cause illness.