关于声现象，下列说法正确的是（　　）

实数a和b在数轴上的位置如图所示，试比较5﹣3a与5﹣3b的大小关系，并说明理由．

    【甲】初，权谓吕蒙曰：“卿今当涂掌事，不可不学！”蒙辞以军中多务。权曰：“孤岂欲卿治经为博士邪！但当涉猎，见往事耳。卿言多务，孰若孤？孤常读书，自以为大有所益。”蒙乃始就学。及鲁肃过寻阳，与蒙论议，大惊曰：“卿今者才略，非复吴下阿蒙！”蒙曰：“士别三日，即更刮目相待，大兄何见事之晚乎！”肃遂拜蒙母，结友而别。

    【乙】初，张咏^①在成都，闻准^②入相，谓其僚属曰寇公奇才惜学术不足尔。及准出陕，咏适自成都罢还，准严^③供帐，大为具待。咏将去，准送之郊，问曰：“何以教准？”咏徐曰：“《霍光传》^④不可不读也。”准莫谕其意，归，取其传读之，至“不学无术”，笑曰：“此张公谓我矣。”

【注】①张咏，北宋太宗、真宗两朝的名臣。②准：寇准，北宋政治家，景德元年任宰相。③严：敬重。④《霍光传》：载《汉书》，传末有“然光不学无术，暗于大理”之语。

    Sudha Chandran, a classical dancer from India, had to have her right leg cut after a car accident. She was also cut off on her bright1road.

    However, she didn't stop 2 In the painful three months that3 Sudha met a doctor who had a(n)4on her leg. So eagerly she wanted to go back to dancing after she had been fitted with a man-made5Sudha knew that she believed in herself and she thought she could 6her dream, so she began her brave journey back to the world of  7— learning to balance, bend, stretch, walk, and turn.

    After every public recital (表演), she would ask her dad about her8.“You still have a long way to go” was the9she used to get in return. In January 1984, Sudha made a historic comeback by giving a10recital in Bombay. She performed in11a great manner that it moved everyone to12and this performance pushed her to the number one position again. That evening when she13her dad the same question, he didn't say 14He just touched her feet as a praise.

    Sudha's comeback was so touching that a film producer decided 15 the story into a hit film,16has moved more and more people.

When someone asked Sudha how she had17to dance again, she said quite 18“YOU DON'T NEED FEET TO DANCE.” Nothing is 19 in this world. If you have the will to win, you can20 anything.