湖南某中学生陈某在网上聊天时与网友李某发生口角，随后两人约定在某地见面了结此事，见面后发生打斗，李某用水果刀刺死陈某。面对此类事，应该（   ）
①以美好道德陶冶自己的心灵，懂得法律规范    ②培养高雅爱好，远离网络
③学会理性分析，对行为与后果有清醒认识        ④树立负责任的人生态度 

鱼被宰杀后，鱼体内的ATP会生成具有鲜味的肌苷酸，但酸性磷酸酶（ACP）会催化肌苷酸分解导致鱼肉鲜味下降．为了研究鱼类的保鲜方法，研究者从草鱼、鮰鱼和鳝鱼中分离得到ACP，并对该酶活性进行了系列研究，相关实验结果如下．下列有关叙述正确的是（　　）

电路图如图所示，电源电动势为20V，内阻r=3Ω，滑动变阻器的最大阻值为20Ω，定值电阻R₀=2Ω．则下列说法正确的是（   ）

Fire is dangerous. What should we do to protect ourselves from the fire? The following is some  16    for you.

How to prepare for a fire?

·Put fire extinguishers(灭火器) in the house. They can help to    17  the fire in a short time. Everyone should know how to use them.

·Fix a smoke alarm(报警器) in the house. It will make a   18    when fire happens. After listening to it, everyone should leave the house quickly.

·Make    19   for escaping (逃脱) from fire. Everyone should know    20 we can escape from quickly. Check the     21    often and see if we can open them easily.

How to escape from the fire?

·  22  open a hot door. It can help fire grow quickly.

·Stay    23 to the floor. The fresher air is near it.

·Roll (打滚) when your clothes burn. 24   is not a good way.

·Never jump off a window. Or you’ll hurt yourself.

If you   25  the fire rules above, you’ll have more chances to live.

()16 A. suggestionsB. plansC. fireD. Water

()17 A. growB. blowC. lightD. Control

()18 A. smokeB. fireC. soundD. Call

()1 A. liftB. plansC. timeD. Floor

()20 A. whereB. howC. whatD. When

()21 A. doorsB. windowsC. desksD. Furniture

()22 A. AlwaysB. UsuallyC. OftenD. Never

()23 A. farB. longC. shortD. Close

()24 A. RunningB. WateringC. RollingD. Covering

()25 A. likeB. breakC. followD. Close

我国为了改善日益恶化的生态环境，建设了许多防护林体系，其中规模较大的是“三北” 防护林和长江中上游防护林。“三北”防护林所起的主要的环保功效是(    )