题目

已知圆C：x2+y2﹣4x﹣5=0． （Ⅰ）判断圆C与圆D：（x﹣5）2+（y﹣4）2=4的位置关系，并说明理由； （Ⅱ）若过点（5，4）的直线l与圆C相切，求直线l的方程． 答案：【考点】直线与圆的位置关系． 【专题】计算题；分类讨论；综合法；直线与圆． 【分析】（Ⅰ）利用圆C与圆D的连心线长=圆C与圆D的两半径之和，判断圆C与圆D：（x﹣5）2+（y﹣4）2=4的位置关系； （Ⅱ）分类讨论，利用圆心C（2，0）到直线l的距离=半径，求直线l的方程． 【解答】解：（Ⅰ）∵圆C的A Wonderful Christmas GiftAnn and her mother had lived in a small cottage as long as Ann could         ．Christmas was so close．Ann wished she could get a new         with lace as a wonderful Christmas gift．But Ann did not want to ask her Mom for a new dress．She knew how hard her mom worked to         both ends meet．Maybe she could make a         —maybe Santa Claus would come…It was not just gift that         Ann．It was her mother．Nowadays she was working overtime and looked          and worn out．The days passed and soon it was Christmas Eve．Ann went to bed with a         heart．She knew that there would be         gifts for her．Ring…．Ring…Ann jumped，hearing alarm．She suddenly remembered it’s Christmas day．Without much hope she looked          there were any gifts for her．Wonder of wonders! There lay a beautiful packet         with a red ribbon．Ann         opened the package．It was a pretty frock with attractive lace．The material was soft and silky         the hard material of the dresses she usually wore．She checked the gift carefully to         who gave her the frock．Suddenly a small piece of paper fell out．Ann         started to read the note．“Dear Ann，This frock is gifted to you for being a good girl．Hope you continue to do good things and help your mother．   Yours， Santa Claus”Ann felt that there was something         about this note．She         the note carefully. Then it struck her．She realized this       is her mother's．Her mother had worked overtime to        money to buy this expensive sift．Ann was happy beyond         ．She knew that she is the          girl to have such a wonderful mother as a wonderful Christmas gift.【小题1】A．rememberB．imagineC．think D．speak【小题2】A．packetB．hatC．doll D．dress【小题3】A．earnB．makeC．put D．get【小题4】A．promiseB．decisionC．plan D．wish【小题5】A．worriedB．discouragedC．ashamed D．surprised【小题6】A．happyB．energeticC．paleD．miserable【小题7】A．1ightB．heavyC．tired D．cheering【小题8】A．fewB．someC．no D．any【小题9】A．ifB．thoughC．as D．because【小题10】A．attachedB．tiedC．packed D．carried【小题11】A．patientlyB．calmlyC．excitedlyD．quietly【小题12】A．1ikeB．unlikeC．dislike D．1ikely【小题13】A．point outB．bring outC．hand out D．find out【小题14】A．carelesslyB．nervouslyC．eagerly D．disappointedly【小题15】A．familiarB．similarC．strange D．unique【小题16】A．1ooked intoB．made use ofC．wrote down D．took away【小题17】A．dressB．handwritingC．note D．packet【小题18】A．offerB．winC．spend D．save【小题19】A．reachB．praiseC．words D．power【小题20】A．bestB．poorestC．greatest D．luckiest