How can recycling help in protecting the environment?When people recycle, theyproduce less trashand help .
查看答案
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
物光和参考光的夹角应当
A. 约等于90度
B. 约等于30度
C. 越小越好
以下哪种不属于新媒体?( )
A. 广播
B. 数字电视
C. 手机
D. 计算机