题目

不能用2H + + CO32－ == CO2 ↑+H2O表示的反应是      A．醋酸溶液与碳酸钠溶液反应     B．稀硝酸与碳酸钠溶液反应 C．稀硫酸与碳酸钾溶液反应           D．硫酸氢钠溶液与碳酸钾溶液反应 答案：AWhen the weather turns warm, everyone wants to be in or around the water. Learning how to keep safe is necessary if you plan to go swimming.“Buddy up!” Always swim with a partner, every time-and this is very important. Even experienced swimmers can become tired or face sudden accidents, which might make it difficult to get out of the water. When you swim together, you can help each other or go for help in a minute.Get skilled. It’s good to go be fully prepared. Learning some life-saving skills can help you save a life. A number of organizations offer free classes to both beginning and experienced swimmers and boaters. Check with local hospitals, or the Red Cross.Know your limits (极限). Swimming an be a lot of fun and you might want to stay in the water as long as possible. If you’re not a good swimmer or you’re just learning to swim, don’t go in water that’s so deep for you and don’t try to keep up with skilled swimmers. That can be dangerous, especially when your friends are challenging you.If you are a good swimmer and have had lessons, keep an eye on friends who aren’t as comfortable or as skilled as you are. If they or you are getting tired, you should take a break for a while.Swim in safe areas only. It’s a good idea to swim only in places that are directed by a lifeguard. No one can expect changing ocean currents (水流), sudden storms, or other dangers. In the event that something does go wrong, lifeguards trained in life-saving skills are ready to help.Swimming in an open body of water like a lake is different from swimming in a pool. Do your research so you know where not to swim, and pay attention to any warning sign(警告标志) posted in the area.­                       小题1:     on swimming safetySwim with a partnerIt is very 小题2:     to go swimming with partners.Partners who are 小题3:     together can help each other or ask for help at once.Make full小题4:    Learning some life-saving skills can be very 小题5:     during a sudden danger.小题6:     free classes offered by local hospitals, or the Red Cross.Know your limitsDo not swim in the water that is too deep.Do not try to swim too小题7:     to catch up with skilled swimmers.小题8:     out for your partners if you are an experienced swimmer.Swim in safe areasSwim in places where there is a 小题9:    .There is 小题10:     between swimming in a pool and in the lake.