问题 单项选择题

患者,男性,75岁,牙列缺失时间长,习惯下颌前伸,左下牙槽嵴骨吸收较右侧明显,1周前全口义齿修复。

患者诉戴全口义齿讲话时和进食时上下牙有撞击声,可能是由于

A.排牙不准确

B.下颌前伸

C.下颌后退

D.垂直距离过低

E.垂直距离过高

答案

参考答案:E

单项选择题
阅读理解

阅读理解

      Even plants can run a fever, especially when they're under attack by insects or disease. But unlike

human, plants can have their temperature taken from 3,000 feet away-straight up. A decade ago,

adopting the infrared(红外线)scanning technology developed for military purposes and other satellites,

physicist Stephen Paley came up with a quick way to take the temperature of crops to determine which

ones are under stress. The goal was to let farmers precisely target pesticide(杀虫剂)spraying rather than

rain poison on a whole field, which invariably includes plants that don't have pest problems.

     Even better, Paley's Remote Scanning Services Company could detect crop problems before they

became visible to the eye. Mounted on a plane flown at 3,000 feet at night, an infrared scanner measured

the heat emitted by crops. The data were transformed into a colourcoded map showing where plants

were running "fevers". Farmers could then spotspray, using 50 to 70 percent less pesticide than they

otherwise would.

      The bad news is that Paley's company closed down in 1984, after only three years. Farmers resisted

the new technology and longterm backers were hard to find. But with the renewed concern about

pesticides on produce, and refinements in infrared scanning, Paley hopes to get back into operation.

Agriculture experts have no doubt the technology works. "This technique can be used on 75 percent of

agricultural land in the United States, " says George Oerther of Texas A & M. Ray Jackson, who recently retired from the Department of Agriculture, thinks remote infrared crop scanning could be adopted by the end of the decade.  But only if Paley finds the financial backing which he failed to obtain 10 years ago.

1. Plants will send out an increased amount of heat when they are________.

A. facing an infrared scanner

B. sprayed with pesticides

C. in poor physical condition

D. exposed to excessive sun rays

2. In order to apply pesticide spraying precisely, we can use infrared scanning to________.

A. estimate the damage to the crops

B. draw a colourcoded map

C. measure the size of the affected area

D. locate the problem area

3. Farmers can save a considerable amount of pesticide by________.

A. resorting to spotspraying

B. transforming poisoned rain

C. consulting infrared scanning experts

D. detecting crop problems at an early stage