催化裂化反应机理中，大阳碳离子进行裂化反应时是（）位断裂A.а B.β C.б 发布时间：2017-11-14 06:56 │ 来源：www.tikuol.com 题型：单项选择题 问题： 催化裂化反应机理中，大阳碳离子进行裂化反应时是（）位断裂A.аB.βC.б
题型：单项选择题 带电量分别为+4Q和-6Q的两个相同的金属小球，相距一定距离时，相互作用力的大小为F。若把它们接触一下后，再放回原处，它们的相互作用力的大小变为（ ）A．F/24B．F/16C．F/8D．F/4 查看答案
题型：单项选择题 完形填空。 Now that I am no longer young, I have friends whose mothers have passed away. I have heardthese sons and daughters say they never fully appreciated their mothers__1__it was too late to tell them. I am blessed (赐福) with the dear mother who is still alive. I__2__her more each day. My mother does not change, but I__3__. As I grow older and wiser, I realise__4__an extraordinaryperson she is. How__5__that I am unable to speak these words in her__6__, but they flow easilyfrom my pen. How does a daughter begin to thank her mother for life itself? For the love, patience and just__7__hard work that go into__8__a child? For running after a toddler (学走步的小孩), for understanding a__9__teenager, for tolerating a college student who knows__10__? For waiting for the day when a daughter__11__how wise her mother really is? How does a__12__woman thank a mother for__13__to be a mother? For being ready __14__ advice (when asked) or keeping __15__when it is most appreciated? For not saying, "I told you so",when she could have uttered these words__16__? For being__17__herself-loving, thoughtful, patient,and forgiving? I don't know how, dear God, except to ask you to bless her as richly as she__18__and to help melive up to the example she has__19__. I pray that I will look as good in the eyes of my children as mymother__20__in mine.( )1.A. as ( )2.A. approve ( )3.A. do ( )4.A. how ( )5.A. sad ( )6.A. absence ( )7.A. common ( )8.A. raising ( )9.A. childish ( )10.A. anybody ( )11.A. detects ( )12.A. pretty ( )13.A. failing ( )14.A. by ( )15.A. silent ( )16.A. dozen times ( )17.A. valuably ( )18.A. devotes ( )19.A. set ( )20.A. sees B．that B．appreciate B．have B．that B．glad B．presence B．plain B．rising B．energetic B．nobody B．discovers B．foolish B．intending B．with B．quiet B．a dozen of timesB．essentially B．deserts B．settled B．finds C．until C．need C．did C．who C．comic C．appearance C．normal C．developing C．fearless C．everything C．recognises C．green C．continuing C．at C．cool C. dozens of times C．commonly C．deserves C．placed C．is D．when D．resemble D．will D．what D．tragic D．existence D．usual D．training D．moody D．nothing D．realises D．grown D．keeping D．on D．noiseless D．dozen of timeD．virtually D．desires D．fixed D．looks 查看答案