题目

设是实数，则是的       （   ） A．充分而不必要条件          B．必要而不充分条件 C．充要条件                  D．既不充分也不必要 答案：a23、If you do not use your arms or your legs for some time, they become weak．When you start using them again, they slowly become strong again．Everybody knows that．Yet（然而）many people do not seem to know that memory works in the same way． When someone says that he has a good memory, he really means that he keeps his memory in practice by using it．When someone else says that his memory is poor, he really means that he does not give it enough chance to become strong． If a friend says that his arms and legs are weak, we know that it is his own fault （过错）．But if he tells us that he has a poor memory, many of us think that his parents should be blamed（责备）, and few of us know that it is just his own fault． Have you ever found that some people can’t read or write but usually they have better memories? This is because they cannot read or write and they have to remember things; they cannot write them down in a little notebook．They have to remember days, names, songs and stories; so their memory is practicing all the time．So if you want to have a good memory, learn from the people：practice remembering． （   ）1．Which is right?     A． Your arms or your legs will become weak when you use them． B． Your memory works in the same way as your arms and legs． C． Everybody knows that memory works in the same way as their arms and legs． D． Your memory can’t become strong again when you use them again． （   ）2．If you want to have a good memory, you must________．     A． practice it                           B． not give it enough chance to become strong C． have clever parents                          D． use your arms and legs often （   ）3．One has a bad memory because of _________．     A． his own fault                         B． his parents’ fault C． his teachers’ fault                     D． his strong arms and legs （   ）4．Many people who can’t read and write can remember things well because________． A． they have to remember                   B． they can’t write them down C． they practice remembering                D． they can remember things quickly （   ）5．The writer tells us：__     A． a good memory comes from practice        B． a good memory needs strong arms and legs C． parents can make us clever                    D． to remember days, names and song 评卷人 得分 七、完成句子 （每空？ 分，共？ 分）