如果某细胞兴奋性周期的绝对不应期为2ms，理论上每秒内所能产生和传导的动作电位数最多 发布时间：2017-12-29 09:20 │ 来源：www.tikuol.com 题型：单项选择题 问题： 如果某细胞兴奋性周期的绝对不应期为2ms，理论上每秒内所能产生和传导的动作电位数最多不超过A．50次B．100次C．400次D．500次
题型：单项选择题 A little girl thought she was not as beautiful _31_other girls,and nobody liked her. So she was always 32__ and didn’t like to talk to others. 33 _ ,one day,her mother gave her a beatiful hair clip. When she wore it,she looked 34__ than before. She decided 35 it to school.On her way to school, she found that everyone she saw smiled at her. Most of them said “Hello” to her, but this 36___ happened before. She thought that beautiful hair clip brought them all. She was so happy about all of the great things. Although she didn't 37 her classmates about her beautiful hair clip, they want to know what happened to her. 38 she went back home, her mother asked her, “Did you know you 39 your hair clip? I found it at the door this morning.”She understood that she didn’t wear the hair to school at all.It was not important what we wear or how we look. The most important thing is 40 we think of ourselves.小题1:A．than B．likeC．asD．from小题2:A．happyB．excited C．sad D．outgoing小题3:A．ButB．HoweverC．soD．because小题4:A．much beautifulB．much more beautiful C．uglierD．more ugly小题5:A．to wearB．wearingC．wearD．wore小题6:A．alwaysB．often C．sometimes D．never小题7:A．sayB．talk C．speakD．tell小题8:A．ThenB．When C．BeforeD．Until小题9:A．wore B．broughtC．lost D．took小题10:A．whyB．how C．that D．what 查看答案
题型：单项选择题 （6分）2011年春季至2012年夏季的连续干旱使我国的西南地区受灾严重。农作物大量减产或绝收，请回答：（1）干旱造成大量动植物死亡，这一现象说明A．生物能影响环境B．生物能适应一定的环境C．非生物因素能影响生物的生存D．生物与环境可以相互影响（2）“山上多植树，胜似修水库，有雨它能吞，无雨它能吐”这句谚语说明植物不仅能涵养水源，还可以通过蒸腾作用促进生物圈的 循环。（3）缺水引起农作物减产，因为水是植物光合作用的 ；而且植物生长所需要的无机盐必需溶解在 才能被植物吸收。（4）城市管网漏水，农田大水漫灌，工业生产用重复率不高等水资源浪费现象比比皆是。如果你是一名环保专家，你将对我们的工业、农业及生活用水提供什么建议？（2分） 。 查看答案
题型：单项选择题 锂电池已经成为新一代实用化的蓄电池，该电池具有能量密度大、电压高的特性。锂离子电池放电时的电极反应式为负极反应：C6Li－xe－= C6Li1-x＋xLi+（C6Li表示锂原子嵌入石墨形成的复合材料）正极反应：Li1-xMO2＋xLi+＋x e-= LiMO2（LiMO2表示含锂的过渡金属氧化物） 下列有关说法正确的是A．锂电池充电时电池反应为C6Li＋Li1-xMO2 = LiMO2＋C6Li1-xB．在电池反应中，锂、锌、银、铅各失去1mol电子，金属锂所消耗的质量最小C．锂电池放电时电池内部Li+向负极移动D．锂电池充电时阴极反应为C6Li1-x＋xLi+＋xe－= C6Li 查看答案
题型：单项选择题 * * 手术后护理要点，以下描述正确的是( )。A．会阴擦洗，每日2次B．保持导尿管通畅C．术后24h内即可下床活动D．术后第5d服液状石蜡以软化大便E．术后1～2d可进牛奶等流食 查看答案