制造轴承座、减速箱一般使用()铸铁。A、灰口 B、可锻 C、球墨
题型：单项选择题
问题：
制造轴承座、减速箱一般使用()铸铁。
A、灰口
B、可锻
C、球墨
题型：单项选择题
阅读理解
You may picture firefighters holding a hose (水管) outside of a burning building,but the Golden Eagles Hotshots don't fight fires quite that way.When they go into action,you may not even see a fire truck.
The Hotshots are firefighters who battle fires in wilderness areas.But don't think you'll only find them in
their home state California.Wherever there is a national wildfire emergency,the Golden Eagles Hotshots
could be there.
But these firefighters don't work the same way as firefighters in a big city.They work in areas where
there are large numbers of trees,bushes,and grass.They climb up and down steep hills to clear brush and
burnable debris (残骸). They sometimes use water,but they often fight fire with fire!
They do that by lighting what are called "backfires",which are small,controlled fires that burn up fuel in
the path of larger wildfires.That way,when the Wildfire gets there,it has nothing to burn and nowhere to
go,because all the burnable fuel has already gone up in smoke.
The Hotshots also clear away fuel using oldfashioned hard work.For example,they use a saw to cut
away trees and heavy brush that could catch fire.
Of course there are times when the Golden Eagles Hotshots do have trucks to supply water to the
fires. But the water is limited,and these guys have to rely on hard work more than anything.Physical
fitness is very important.They have to be in great physical shape to handle steep hills and difficult terrain (地形) while carrying a 60-pound pack.
The Golden Eagles Hotshots definitely work hard for their pay.But thanks to their efforts,many lives
have been saved,many houses have not burned,and countless trees are still standing.
1. The firefighters mentioned in the passage________.
A. do much of their work in California
B. avoid climbing steep hills in their work
C. do their work equipped with advanced tools
D. carry out their work mostly in forests and mountains
2. According to the passage,why do the firefighters light "backfires"?
A. To signal for help.
B. To remove obstacles.
C. To protect trees and bushes.
D. To prevent the fire from spreading.
3. What can we learn about the Golden Eagles Hotshots ?
A. They are firefighters working in big cities.
B. Their work requires physical strength.
C. They are voluntary firefighters working for free.
D. They usually hold a hose to put out the fires.
4. What is the author's attitude towards the Golden Eagles Hotshots?
A. Appreciative.
B. Doubtful
C. Worried.
D. Critical.