Directions : The following is a part of a passage about pollution After reading it, you are required to complete the outline below it (No. 46 to No. 50). You should write your answers briefly (in no more than 4 words)on the Answer Sheet correspondingly.
Water can become polluted in many ways. Chemicals from factories, untreated sewage (污水), crop sprays , oil spills and wastes from mines all pollute water. This makes the water unfit for drinking, swimming and bathing. But the damage doesn’ t end there. Polluted water is also unfit for water animals. Water animals that are not killed by pollutants may hold pollutants in their bodies and then pass them along food chains. The people and other animals who are the final consumers in food chains are affected by the pollutants. Detergents (洗涤剂) and agricultural fertilizers are two common pollutants in the water supply. Some water plants thrive (茁壮成长) on the substances found in these two pollutants. As a result, these plants grow rapidly and use up most of the available nutrients in the water environment. Then the plants begin to die and decay. The oxygen in the water supply is used up as a result of this decay. Thus, less oxygen is available for fish and other animals living in the water, and they may die.
Water pollution is very erous:
1. Chemical and wastes pollute water and make the water 1 swimming and drinking.
2. Water animals may pass water pollutants to 2 because they are the 3 in food chains.
3. Detergents and agricultural fertilizers are two 4 in the water supply. Depending on the substances in them, water plants grow rapidly, while it also 5 most of the nutrients in water. Directions :in no more than 4 words