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【单选题】
当变流器工作在逆变状态时,控制角 α应( )。A.
．大于 90°
B.
．小于 90°
C.
．等于 90°
D.
．不一定
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反馈参考答案：
举一反三
【单选题】关于时效和回火的区别，哪一个是正确的
A.
干扰项 1 （不必选）；
B.
干扰项 2 （不必选）；
C.
回火和时效完成后，都要快速冷却；
D.
回火和时效完成后，都要缓慢冷却。
【单选题】Which of the following is true according to the passage?
A.
If you need help, please turn to your teachers.
B.
The traffic moves on the left side of the road in the country.
C.
It is against the law for anyone to buy cigarettes or tobacco.
【单选题】If you __ a fire, please break the glass to sound the fire alarm.
A.
make
B.
find out
C.
invent
D.
discover
【单选题】As soon as you hear the fire and emergency signal, you should ensure that the _____.
A.
ring buoys are thrown overboard
B.
engines are stopped
C.
fire pumps are started
D.
life preservers have been issued to everyone
【单选题】When you are going to put out a fire， you__________. 查看材料
A.
must be careful
B.
should keep air away from it
C.
must know it is dangerous
D.
should cover it with water
【单选题】—Could you give us an account about the big fire? —OK. It was a Friday evening _______the fire broke out and ten persons were killed in it.
A.
where
B.
on which
C.
that
D.
when
【单选题】You should keep furniture or clothes away from a lighted fire because______.
A.
the fire is too low
B.
furniture or clothes block light
C.
there is no guard in the room
D.
furniture or clothes catch fire easily
【单选题】When approaching a fire from win ward, you should shield firefighters from the fire by using_____.
A.
low-velocity fog
B.
high-velocity fog
C.
a straight stream of water
D.
foam spray
【简答题】Knowing how to do in case of fire is important. If a fire break out, what would you do? First, you should warn everyone in the building about the er. Don’t panic or start shouting. Be calmly and a...
【简答题】Escaping a fire is a serious matter. If you know what to do during a fire, you can __1_ _ a life. It is important to know the ways you can use and __2__ them to everyone in the family, such as stairs...
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