问答题

【参考答案】

When you put him on the spot, you can expect to see blue vei......

(↓↓↓ 点击下方‘点击查看答案’看完整答案、解析 ↓↓↓)
<上一题 目录 下一题>
热门 试题

问答题
Today’s policemen in large cities throughout the world rely on modem inventions to help them in their work. In most places motor scooters and police patrol cars have done away with the need to patrol on foot or on horseback. Policemen use telephones, conveniently located throughout their districts, to make immediate contact with headquarters. Radio, television, and computers help to speed the work of the modem force. Even boats and helicopters are part of the equipment of metropolitan police departments. New technical inventions are widely used to fight crime and speed the solution for criminal cases. Electronic computer reduce from hours to minutes the time spent in searching for fingerprints. Witness’s descriptions of a criminal are coded and fed into a computer. The machine then sorts through the picture file of known criminals and selects the name and photograph of the most likely suspect. Lie detectors are used to uncover the truth.
问答题
Petroleum is essentially a nonrenewable natural resource, an almost useless mixture comprised of very useful substances. It exists underground in liquid, solid, semisolid, and gaseous states. The name petroleum is derived from the Latin words petra and oleum, meaning rock oil . Created only by nature but exploited by man, petroleum is a nonrenewable resource because people consume it approximately one million times faster than nature can create it. Timber is a renewable natural resource; it can be harvested, replanted, and then reharvested in a few decades. In a sense, petroleum seeds are being planted today because the natural processes that create petroleum occur continuously. However, the results cannot be harvested for many millions of years. The petroleum that man harvests today was planted 30-6,000 million years ago! That is why petroleum is considered nonrenewable.
相关试题