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英语专八考前自测冲刺题:改错上

分类: 英语  时间: 2019-01-24 17:05:33  作者: 全国等级考试资料网 

本文是英语专业八级考试中的改错题型,供考生在考试前做自我测试之用。

We’ve all used thermometers to measure temperature

but sometimes we need to measure temperature in places you (1) __

can’ t put a thermometer —— for example, inside a rocket engine.

One of the best methods for those really hard-to-get-to

place is based on laser spectroscopy. Light from a laser point- (2) __

ing at the region of interest is absorbed by molecules and some (3) __

of it are re-emitted back towards the source where it can be (4) __

measured. The re-emitted fight is shifted in frequency (changed

in wavelength) by amounts that depend on the molecule and

also the temperature and pressure of the surrounding gas be- (5) __

cause of collisions among the molecules. The single, sharp

frequency from the laser is thus smeared out into a whole

spectrum of frequency whose shape can be used to determine (6) __

the temperature provided so that the molecular transitions and (7) __

line shapes are known. Because it is the main component of

the air, it is convenient to use nitrogen since its molecular (8) __

properties are known from room temperature to temperature

of about 1,200 degree Celsius from experimental measurements. (9)

Although this is a large range, it is far short of what it is needed (10) __

for, some applications.

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