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.