题目

天然存在的金属钫（Fr）极微量。它的21种已知同位素都有放射性。它是碱金属元 素中最重的元素。根据它在周期表中的位置预言其性质，其中不正确的是(    )    A．在空气中燃烧时生成氧化物Fr2O    B．在已知元素中具有最大的原子半径 C．氧化物对应的水化物碱性极强      D．其单质的熔点比金属钠的熔点低Friendship is unconditional and uncritical, based only on mutual respect and the ability to enjoy each other's company. These authority figures never saw the way one of us could do something outrageous, and the rest of us would joke about it for days. We could have fun doing absolutely nothing at all—because the (1)_______ we provided each other with was enough. Rather than discussing operas, Lewinsky, or the weather, we enjoyed just (2)_______ each other without any one of us trying to outsmart the others. Still, I realize that these adults had a(3)_______ to be concerned about the direction my friends were(4)_______; I also was concerned for them, but I wasn't about to (5)_______ them. Many times I would advise my friends that some activity may be (6)_______ or to think things through before doing something, but I would never claim to hold the moral high ground and to condescend to them. When Marvin would begin rolling joints, when Alisa would tell me she skipped school because of a hangover, or when Merriam would tell me that her new boyfriend was in a street gang, I expressed my discomfort with their (7)_______. However, I never (8)_______ them with the threat of taking my friendship away. Contrary to the commercials on television, you can have (9)______ who use drugs. In fact, probably everyone does without (10)______ it. 1. A. gift        B. present          C. company        D. friendship 2. A. hanging around                            B. learning from     C. communicating with           D. joining in 3. A. prejudice B. point              C. suggestion                D. situation 4. A. giving            B. coming        C. heading        D. facing 5. A. ignore          B. upset             C. blame                D. leave 6. A. crazy     B. dangerous             C. boring             D. important 7. A. action            B. lessons                C. words             D. thoughts 8. A. force          B. threaten               C. persuade         D. cheat 9. A. friends         B. girlfriends    C. classmates              D. brothers 10. A. hearing         B. recognizing     C. realizing          D. knowing