题目

“NaCl+CO2+NH3+H2O═NaHCO3+NH4Cl”是著名的“侯氏制碱法”的重要反应，反应生成的NaHCO3（一种盐）达到一定浓度时会从溶液中先结晶出来．下面是4位同学对该反应涉及的有关知识发表的部分见解，其中正确的是（ ） A．这个反应属于复分解反应 B．NaHCO3一定是难溶于水的物质 C．反应后的溶液中存在NH4+ D．结晶出NaHCO3后的溶液中没有Na+There are some easy things you can do to protect(保护) the environment and the earth. Choose ideas from the list or come up with a few of your own. ● Plant flowers, grass or trees.●Whenever you visit a park or beach, take away what you bring there----keep rubbish in a bag until you can put it in a dustbin (垃圾箱).●Turn off the lights, TV sets when you leave the room. This saves (节约)a lot of electricity.●Turn off the tap (水笼头)when you brush your teeth. You can save some water by not letting it run. Also, use a glass cup instead of a paper cup because this saves paper.●Keep the doors and windows closed in winter to keep warm air in.●Give your old books and magazines to a library instead of throwing them away. ●Give your old clothes to poor children you know instead of throwing them away.●Use both sides of paper.●Stop pouring (倒)dirty water into the rivers or the lakes nearby (附近).●Encourage all your friends to do the same things you do to help protect the earth. You don’t have to wait until Earth Day to do these things. Make every day Earth Day.If everyone makes a contribution (贡献)to protecting the environment, the world will become much more beautiful.小题1:From the above, we know that this is ____________.A．a signB．a noticeC．an advertisementD．a proposal (提议)小题2:The writer tells us _____________.A．to throw rubbish into a dustbinB．to pour dirty water into the riverC．to save water by letting it run while we are brushing our teethD．that we can’t do all these things until Earth Day小题3:We can ___________to save paper.A．use a paper cupB．use both sides of paperC．give old books to a libraryD．pick up waste paper at school小题4:Which of the following is WRONG according to the writer?A．Turn off the lights when you leave the room.B．Close the doors in winter.C．Use a paper cup when you brush your teeth.D．Give your old clothes to the poor children.小题5:The main idea of this passage is how to _________.A．save moneyB．save water and electricityC．make better use of old thingsD．protect the earth