In the metals industry, hydrogen is used to prevent metals from tarnishing while undergoin
A.treated by heat
B.heat treatments
C.by heat treatments
D.heat-treated
A.treated by heat
B.heat treatments
C.by heat treatments
D.heat-treated
What is the best title for this passage?
A.The Causes of Industrial Revolution.
B.The Industrial Revolution and Its Significance.
C.The Theory of Division of Labour and Its Significance.
D.Adam Smith, the Economist and Philosopher.
Too much tourism can cause all these problems EXCEPT ______.
A.a bad effect on other industries
B.a change of tourists' customs
C.over crowdedness of places of interest
D.pressure on traffic
According to the passage, what does man care most among the following?
A. Health.
B. Industry.
C. Clean air.
D. The future of the children.
Why do only few pilots retire early?
A.Because pilots are much needed in the airline industry.
B.Because the economy is gloomy.
C.Because the cost of training a pilot is high.
D.Because pilots can not do other jobs.
According to the passage, which of the following statements is CORRECT?
A.The mining industry occupies a minor part in Chile"s GDP.
B.Chilean government should think twice before ratifying the ILO"s Convention 176.
C.San Jose"s mine rescue shows Chile"s remarkable progress in rescue work.
D.It"s high time Chilean government took measures to strengthen its mining safety.
Almost all metals are good conductors, silver______ the best of all.
A.is
B.being
C.has been
D.is to be
Laser beams can be used to bore metals and other hard materials.
A.trim
B.melt
C.drill
D.slice
A.is a good conductor B. is a good insulator
C. are good conductors D. are good insulators