肾区及输尿管前后位摄影,中心线经
A.肚脐
B.肚脐下3cm
C.剑突到肚脐连线中点
D.肚脐到耻骨联合连线中点
E.剑突到耻骨联合连线中点
第3题
Is oxygen the only gas______helps fire burn?
A.that
B./
C.which
D.it
第4题
A fire of escaping liquefied flammable gas is best extinguished by ______.
A.cooling the gas below the ignition point
B.cutting off the supply of oxygen
C.stopping the flow of gas
D.interrupting the chain reaction
第5题
The three basic elements necessary for any fire are ()
A.heat, gas and flames
B.fuel, heat and oxygen
C.heat, nitrogen and fuel
第6题
Fire can help people in many ways. But it can also be very dangerous. Fire can heat (加热) water, warm houses, give light and cook food. But fire can burn things, too. It can burn trees, houses, animals, or people. Sometimes big fires can burn forests.
Nobody knows for' sure how people began to use fire. But there are many interesting old stories about the first time a man or a woman started a fire. One story from Australia tells about a man very, very long time ago. He went up to the sun by a rope (绳子) and brought fire down.
Today people know how to make a fire with matches (火柴). Children sometimes like to play with them. But matches can be very dangerous. One match can burn a piece of paper, and then it might burn a house.. A small fire can become a big fire very fast. Fires kill many people every year. So you must be careful with matches. You should also learn to put out (熄灭) fires. Fires need oxygen (氧气). Without oxygen they will die. There is oxygen in the fire. Cover a fire with water, sand, or sometimes with your coat. This keeps the air away from a fire and kills it. Be careful with fire; and it will help you. Be care less with fire, and it will burn you.
How did people begin to use a fire?
A.We know how people began to use fire.
B.Nobody knows how to make a fire.
C.It was an Australian who started a fire.
D.We are not sure how people started a fire.
第7题
Those who ______ will burn themselves.
A.play a fire
B.play fire
C.play the fire
D.play with fire
第8题
It was so cold that they kept the fire ______ all night.
A. to burn
B. burn
C. burning
D. burned
第9题
Gas masks ______.
A.should be worn while fighting a fire
B.can be used in atmospheres deficient in oxygen
C.filter contaminants from air that is to be breathed
D.may be substituted for a self-contained breathing apparatus
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