两台泵相似,则所有对应叶片角应()。A、相等 B、相似 C、成比例 D、不确定

题型:单项选择题

问题:

两台泵相似,则所有对应叶片角应()。

A、相等

B、相似

C、成比例

D、不确定

考点:电厂水化验员考试中级电厂水化验员中级电厂水化验员题库
题型:单项选择题

房间隔缺损和室间隔缺损的主要区别是

A.心脏呈二尖瓣形
B.肺动脉段高度隆起
C.肺门搏动更明显
D.左心房不大
E.左心室不大

题型:单项选择题

男性,24岁。左下胸被小口径步枪击伤1小时。X线胸片:左肋膈角消失,弹头存留于腹腔内。首先要考虑的诊断是()。

A.左胸开放伤

B.左膈肌贯通伤

C.左胸盲管伤

D.胸腹联合伤

E.胸腹复合伤

题型:单项选择题

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

4. The application of infrared scanning technology to agriculture met with some difficulties-________.

A. its high cost

B. the lack of official support

C. the lack of financial support

D. its failure to help increase production

5. Infrared scanning technology may be brought back into operation because of________.

A. full support from agricultural experts

B. growing concern about the excessive use of pesticides on crops

C. the forceful promotion by the Department of Agriculture

D. the desire of farmers to improve the quality of their produce

题型:单项选择题

瞳神中医学又称,不包括()

A.瞳子

B.瞳人

C.瞳孔

D.瞳仁

E.金井

题型:单项选择题

溶解氧腐蚀的金属特征是()。

A、金属均匀变薄

B、金属表面有小鼓包

C、金属脆化

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