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更多“Once harm________(do) to the e…”相关的问题
Once environmental damage （), It takes many years for the system to recover.
A.has done
B.does
C.is to do
D.is done
A.How do you go to the library
B.How often do you go to the library
C.When do you go to the library
A.had us do
B.had us to do
C.had us done
D.had us doing
A.boat
B.empty
C.space
D.arrival
A.It's very important.
B.Once a week.
C.I'll stay here for a long time.
D.I'll be here for two or three days at least.
A.Once done,you do not need to touch any files again.
B.You can label the files and folders with familiar names.
C.You need to put things similar in the same folder.
A.has been made
B.made
C.been made
D.having been made
A．keep up with
B．give away from
C．go back on
D．lose sight of
A. 曾经你设置过了具体的时间表，下一步就是采取日常行动，尽自己的职责。
B. 一旦你已经设置了具体的时间表，下一步就是每天采取行动，做自己的事情。
C. 一旦你已经设置了具体的时间表，下一步就是每天行动起来，尽自己的职责。
We all have to learn how to stop wasting our limited water. One of the steps we should take is to find ways of reusing it. Experiments have already been done in this field.
Today in most large cities, fresh water is used only once, then it runs into waste system. But it is possible to pipe the used water to a purifying factory. There it can be filtered and treated with chemicals so that it can be used again, just as it were fresh from a spring.
But even if every large city purified and reused its water, we still would not have enough. Then we could turn to the oceans. All we’d have to do to make use of the seawater on earth is to get rid of the salt.
This process is called desalinization, and it is already in use in many parts of the world.
The way to stop wasting our limited water is to （）.
A.do experiments with water
B.purify the used water and reuse it
C.use fresh water once again
D.make use of seawater
