阈电位是指A．细胞发生反应的最适刺激 B．Na+ 通道开放的膜电位值 C．正反馈Na 发布时间：2018-06-18 12:07 │ 来源：www.tikuol.com 题型：单项选择题 问题： 阈电位是指A．细胞发生反应的最适刺激B．Na+ 通道开放的膜电位值C．正反馈Na+ 内流的临界膜电位D．正反馈K+ 外流的临界膜电位E．Na+ 通道开始关闭的膜电位值
题型：单项选择题 完形填空： A little boy invites his mother to his school's first teacher-parent meeting. To the little boy's disappointment, she said she would 1 . This would be the first time that his classmates and teacher 2 his mother and he felt ashamed (羞愧) of what she looked like. 3 she was a beautiful woman, there was a deep scar (伤痕) that covered the whole right side of her face. The boy never wanted to 4 why or how she got the scar. At the meeting, everyone was impressed by the kindness and natural beauty of his mother in spite of the scar,but the little boy still felt uncomfortable and 5 himself from everyone's view (视野). However, he could hearthe 6 between his mother and his teacher. The teacher asked 7 , "How did you get the scar on your face?"The mother replied, " 8 my son was a baby, he was in a room that caught fire. Everyone was 9 afraid to goin because the fire was terrible, so I went in. As I was running toward his bed, I saw a long 10 of wood coming down and I placed myself over him trying to 11 him from hurt. I was knocked down, but luckily, a fireman came in and saved 12 of us." She said slowly, "This scar will be 13 , but until now, I have never felt sorry for what I did." At this point, the little boy came out running towards his mother with tears in his eyes. This was his first timeto hear the story. He 14 her in arms and felt the great 15 from his mother. ( ) 1. A. listen ( ) 2. A. met ( ) 3. A. Because ( ) 4. A. tell about ( ) 5. A. enjoyed ( ) 6. A. voice ( ) 7. A. carefully ( ) 8. A. As ( ) 9. A. so ( ) 10. A. bit ( ) 11. A. keep ( ) 12. A. both ( ) 13. A. leaving ( ) 14. A. pushed ( ) 15. A. thank B. talk B. looked at B. Though B. think about B. helped B. talk B. happily B. When B. much B. pair B. make B. either B. changing B. held B. pride C. go C. watched C. So C. worry about C. hid C. speech C. loudly C. Since C. quite C. piece C. help C. all C. missing C. put C. sadness D. work D. found D. But D. know about D. taught D. conversation D. angrily D. Until D. too D. kind D. save D. several D. lasting D. closed D. love 查看答案
题型：单项选择题 写出带有下面部首的字并组词。火_____（ ）_____（ ）_____（ ）皿_____（ ）_____（ ）_____（ ）礻_____（ ）_____（ ）_____（ ）饣_____（ ）_____（ ）_____（ ） 查看答案
题型：单项选择题 中国政府11月26日宣布：到2020年，单位GDP碳排放强度从2005年的基础上降低40%-45%的目标，实现这一目标主要是控制[ ]A．臭氧空洞扩大 B．温室效应进一步加剧 C．酸雨的形成D．水环境恶化 查看答案
题型：单项选择题 以下说法错误的是（）A.肺动静脉瘘多见于20～30岁发病，而肺隔离症多见于老人B.肺动静脉瘘供血动脉一般为肺动脉，引流静脉为肺静脉，而肺隔离症是有主动脉分支供应C.肺动静脉瘘要与肺内结节、肿块鉴别D.肺动静脉瘘常可合并肺外其他部位动静脉畸形，引起毛细血管扩张E.肺隔离症需与肺囊肿、肺肿瘤鉴别 查看答案