题目

如图所示的浮标放在水中，当水温度上升、体积膨胀导致密度下降时。此过程中若浮标体积保持不变，则A. 浮力变大，露出水面体积变小B. 浮力变小，露出海面体积变大C. 浮力不变，露出海面体积变大D. 浮力不变，露出海面体积变小 答案：【答案】D【解析】因为浮标始终漂浮，并且浮标重力不变，故浮力等于重力，并且浮力不变；又因为水密度减小，由F浮=gＶ排可知，浮标排开水的体积变大，则露出海面体积变小。故D正确。完形填空 　　London-life for Cathy Hagner and her three children is very tiring. 　　Their 1 school day and her job as a lawyer's assistant are busy enough. 2 Hagner also has to take the two boys to soccer or hockey or basketball while dropping off her 3 at piano lessons or Girl Scout Club. 　　 4 , the exhausted （筋疲力尽的） family doesn't get home until 7 p. m. . There is just time for a quick 5 before homework. 　　In today's world , middle-class American and British parents treat their children 6 they were competitors 7 for some finishing line. 　　Parents take their children from activity to activity to make their future 8 . It seems that raising a man much cleverer than anyone else had become a more 9 goal than raising a happy and well-balanced child. 　　“ 10 across the country are reporting a growing number of children 11 from stomachaches and headaches 12 exhaustion and pressures” says child expert William Doherty of the University of Minnesota. 　　Teachers are 13 exhausted kids in the classroom. It's a very serious problem. Many children attend 14 clubs necessity. But competitive pressures also 15 an explosion of activities. They 16 sports, language, music and maths classes for children as 17 as four. 　　“There is a new trend （趋势） among many parents. You have to tap all of your child's ability at a young age. 18 you will let them down , ” says Terry Apter, a Cambridge-based child and adolescent psychiatrist （青少年精神病专家）. 　　“It isn't entirely 19 : there have always been such parents. But what was seen as strange behaviour before is now well 20 .” 1． [　　] A．halfB．part C．fullD．normal 2． [　　] A．OrB．So C．ButD．For 3． [　　] A．daughterB．sons C．girlsD．kids 4． [　　] A．OftenB．However C．ThoughD．Seldom 5． [　　] A．lunchB．supper C．breakfastD．tea 6． [　　] A．even ifB．as if C．now thatD．in case 7． [　　] A．hopingB．caring C．callingD．racing 8． [　　] A．equalB．smooth C．excitedD．bright 9． [　　] A．exactB．excellent C．difficultD．important 10． [　　] A．DoctorsB．Lawyers C．EngineersD．Businessmen 11． [　　] A．dyingB．preventing C．sufferingD．learning 12． [　　] A．due toB．so as to C．according toD．referring to 13． [　　] A．dealing withB．playing with C．going on withD．getting on with 14． [　　] A．grown-upB．body-building C．after-schoolD．night 15． [　　] A．growB．reduce C．stopD．create 16． [　　] A．haveB．enjoy C．teachD．include 17． [　　] A．oldB．young C．manyD．much 18． [　　] A．andB．so C．orD．unless 19． [　　] A．oldB．new C．wrongD．right 20． [　　] A．respectedB．accepted C．refusedD．managed