个体发育过程中最早合成和分泌的抗体是（） A.IgG B.IgM C.IgA D.I 发布时间：2017-06-13 23:32 │ 来源：www.tikuol.com 题型：单项选择题 B型题 问题： 个体发育过程中最早合成和分泌的抗体是（）A.IgGB.IgMC.IgAD.IgDE.IgE
题型：单项选择题 B型题 化学实验中，有很多实验操作步骤必须严格按要求进行，否则或实验失败或发生危险．例如，用酒精灯给试管中固体加热时，应该先对试管进行预热，过一会再固定在有药品部位加热，否则试管会因受热不均匀而炸裂．请你依照示例，填写下表中的空格：必须遵循操作先后顺序的实验先进行的操作后进行的操作（1）制取氧气______再向容器中装药品（2）加热高锰酸钾制取氧气，并用排水法收集氧气结束时____________（3）__________________ 查看答案
题型：单项选择题 B型题 中俄两国元首于2005年7月正式宣布，为全面推动两国战略协作伙伴关系向前发展，双方决定互办以经济、文化为主要内容的“国家年”活动。这有利于[ ]①提高我国对外开放的水平 ②我们吸收西方的一切文化成果③世界不同文明之间的交流与沟通 ④促进中国特色社会主义先进文化的发展A．①②③B．①②④C．①③④D．②③④ 查看答案
题型：单项选择题 B型题 完形填空。 What a busy day! The three boys were fed, bathed and changed in to their nightclothes. Mary had 1 them a story and finally they were asleep. "Babysitting (照看) the three boys aged eight, six and four is extremely 2 ," she thought. "Sleep," she considered, "if only I could!" But she had difficult homework to complete. Leaning back, she 3 her feet onto the sofa to get comfortable. Whoever said babysitting was a(an) 4 way to make money obviously hadn't met the three boys, she thought. The television was on, the room was warm, andthe lights were dim. Mary's 5 felt heavier and heavier. I mustn't sleep, she thought which was 6 whatshe did, of course. Strangely enough, she soon 7 that she was a world-famous chef (主厨). She made a 8 and wore diamonds and designer clothes. Most days she relaxed by the pool, meeting the rich and famous or 9 -her favorite hobby. She 10 took the leading role in her own TV show. That is, until she became too 11 . "I am definitely the best in the world," she thought, as she prepared a tasty chicken dish. But 12 seemed to go right. She spilt the flour, she dropped an egg and she cut her finger. Despite all the troubles, she 13 to get the chicken into the dove. Soon, smoke blanketed the room. The chicken was on fire. 14 set in, but Mary could not run-she was 15 to the spot. She tried hard to move, but could not, 16 a sharp sound awoke her. She got shocked and confused 17 was pouring from the kitchen. Rushing to investigate, she was met by three 18 little faces and some very burnt bread. "Sorry, we were hungry and you were 19 , so we triedto make some bread," explained a boy. Relieved, Mary made them a snack and sent them back to bed. She 20 them never to fall asleep on the job again! ( )1. A. given ( )2. A. successful( )3. A. shook ( )4. A. difficult ( )5. A. eyes ( )6. A. nicely ( )7. A. realized ( )8. A. decision ( )9. A. cooking ( )10. A. just ( )11. A. selfish ( )12. A everything ( )13. A. tried ( )14. A. Panic ( )15. A. frozen ( )16. A. because ( )17. A. smoke ( )18. A. cheerful ( )19. A. busy ( )20. A. promised B. written B. helpful B. put B. boring B. mind B. exactly B. remindedB. fortune B. reading B. ever B. proud B. something B. arranged B. Pain B. dragged B. until B. light B. strange B. hungry B. allowed C. told C. tiring C. bent C. important C. heart C. curiously C. learnt C. businessC. running C. even C. stubborn C. anything C. managed C. Noise C. pushed C. as C. water C. guilty C. worried C. expected D. taught D. surprising D. kept D. easy D. legs D. carelessly D. dreamt D. plan D. babysitting D. only D. sensitive D. nothing D. prepared D. Stress D. brought D. unless D. fire D. confident D. asleep D. persuaded 查看答案
题型：单项选择题 B型题 我国计划用5年左右时间，全面普查、系统收集全国2200个农业县的（），鉴定评价、编目入库保存种质资源7万份，实现珍稀、野生资源有效收集和保护，资源保存总量大幅提升，结构优化。A.畜牧物种质资源B.禽畜物种质资源C.植物种质资源D.农作物种质资源 查看答案