Pollution in the air reduced the _________ near the airport.

A . dust entering the high pressure stage B . lube oil carbonization C . discharge pulsations D . inter-stage vapor lock

A . high temperatures B . low temperatures C . wet D . dirty

A . flashing point B . combustion point C . auto-ignition point D . lower explosive limit

A . catch plates B . dampers C . regulating valves D . fa

A . fuel oil B . sludge C . oil refuse D . All of the above

A . air compressor B . diffuser C . after-cooler D . ventilator

A . Moisture separator B . Vacuum breaker C . Lubricator D . Non-return valve

M: Everyone wants to stop it, but it is a difficult problem to solve. Meat pollution is mused by things people need. W: What do you mean？ M: Well, automobiles and airplanes cause pollution but they also provide transportation. W: Right. And factories cause air pollution but they provide people with jobs and products. M: Cities are the worst offenders. In crowded cities, factories and cars can add tons of pollution to the air every day. W: Yes. When I drove, to town yesterday, the clear air changed. It seemed like a dark cloud hung over the city. M: Nobody likes air pollution. It smells bad; it makes it difficult to breathe. W: True, it even damages the plants that provide tis with food. No wonder we get sick. It's dangerous to everyone's health. M: I think everyone knows it is a serious problem. When air pollution can even damage strong materials like steel and concrete; think what it does to poor humans. W: It is terrible, and yet we do need some things that cause it. We'll have to try to figure out a solution. (20) A．Most people don't think it is a serious problem. B．Most of our pollution is caused by things people need. C．The government has not spent enough money to stop it. D．The seriousness of pollution has not been realized by the government.

A．Right B．Wrong C．Not mentioned

A.Discharge a cylinder of nitrogen into the container B.Shade the container and periodically hose it down C.Seal any ventilation openings and add dry ice D.Spread ice over the top layer and in any voids within the container

A．The air pollution is caused by the development of industry. B．The city was poor because there wasn't much industry then. C．The woman's exaggerating the seriousness of the pollution. D．He might move to another city very soon.

A．Having looked B．Looked C．Looking D．To look

A．cause widespread damage in the countryside B．affected the entire eastern half of the United States C．had damaged effect on health D．existed merely in urban and industries areas

A.They function as part of a purification process. B.They are dwarfed by the pollutants produced by human activities. C.They are less harmful to living beings than are other pollutants. D.They have existed since the Earth developed.

The combination of sea/air transportation has in itself some advantages, such as () A．reducing cost of exports B． the high reputation of airlines C． the economy of sea transport D． the speed of air transport 此题为多项选择题。

The United Nations Environment Program says that air pollution reduces the amount of crops produced, h also reduces the nutrient level of crops. As a result, both the buyer and the seller of crops are hurt by air pollution. The UN says dirty air is a major source of metal in crops. These metals include lead, zinc and copper. These metals can build up to dangerously high levels in the parts of plants that people eat. The German Appropriate Technology Exchange, GATE, reports that eating these metals can cause developmental problems and low intelligence levels among children. Some kinds of cancers and kidney damage have also been linked to metals in crops. Who is hurt by air pollution？ A．The buyer. B．The seller. C．Both the buyer and the seller. D．None.

是 否

此题为判断题(对，错)。