What is carpooling?People instead of driving cars of their own separately.
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How can we help to reduce greenhouse gases when using computers?the computer when we are through with it; put it on stand-by when we leave it for a while.
How can recycling help in protecting the environment?When people recycle, theyproduce less trashand help .
What are the little things we can do to make a difference? List some.Saving 1 , using2, riding3, taking buses and walking, planting trees, recycling, taking corporate actions, learning more about global warming, joining environmental groups, etc.
摆放光路时,应当使物光光程和参考光光程
A. 尽量相等
B. 差别最大