Sample 2.
An American 1 has successfully tested a way to clean waste water without chemicals. The 2 uses green plants. Researcher William Jewell is an agricultural engineer at Cornell University in New York State. He calls his cleaning method the nutrient film techique. He says it is very simple. It is based 3 a fact that waste water is an excellent plant food.
The United States Environmental Protection Agency is supporting Professor Jewell's experiments. The tests were carried 4 at an existing waste water treatment center in the northeastern state of New Hampshire. The scientists put plants in narrow containers 5 a glass building. One end of each container was a little higher than the other and waste water was directed down the containers through the plants' thick roots. 6 expected, the roots trapped the wastes in the water and used them for food. At the same time, the plants produced natural gas. The gas could be 7 and sold as fuel.
Professor Jewell says his nutrient film technique is more 8 than most chemical systems. He also says it can produce clean water for about half the cost. And he says, the technique can be used in treatment centers fueled 9 the sun. Four places in Florida 10 are using green plants to clean their waste water.
1.［A］ observer ［B］ research ［C］ explorer ［D］ expositor 2.［A］ means ［B］ ways ［C］ method ［D］ technique 3.［A］ at ［B］ for ［C］ in ［D］ on 4.［A］ on ［B］ off ［C］ out ［D］ over 5.［A］ inside ［B］ outside ［C］ beneath ［D］ opposite 6.［A］ As ［B］ So ［C］ As were ［D］ So were 7.［A］ concentrated［B］ organized［C］ assembled［D］ collected 8.［A］ affective ［B］ effective［C］ frequent ［D］ efficient 9.［A］ by ［B］ from ［C］ in ［D］ under 10.［A］ yet ［B］ still ［C］ already ［D］ exactly
