{"ops":[{"insert":"十三、数词\n1.数词分为两类：基数词和序数词，基数词可以表示数量的多少，如：\n我要吃三根胡萝卜里的”三“就是基数词，表胡萝卜的数量；\n而序数词可以表顺序的先后，如：\n我要吃第三根胡萝卜里的”第三“就是序数词，表我要吃的具体是哪一根胡萝卜。\n2.基数词的构成形式\n个位：\n"},{"attributes":{"class":"normal-img"},"insert":{"native-image":{"alt":"read-normal-img","url":"https://b1.sanwen.net/b_article/19f4d72214e3d4888164548253f15c621b9b71ed.jpg","width":2000,"height":1200,"size":290527,"status":"loaded"}}},{"insert":"11-19\n"},{"attributes":{"class":"normal-img"},"insert":{"native-image":{"alt":"read-normal-img","url":"https://b1.sanwen.net/b_article/6794448b02f7ac403794c7cf08f669728379907d.jpg","width":2000,"height":1200,"size":347272,"status":"loaded"}}},{"insert":"20-90\n"},{"attributes":{"class":"normal-img"},"insert":{"native-image":{"alt":"read-normal-img","url":"https://b1.sanwen.net/b_article/92f4f7e8b9d879657aeeef6cd2c2bfb5ffe2611c.jpg","width":2000,"height":1200,"size":345237,"status":"loaded"}}},{"insert":"几十几，先写几十再写几，中间加上连字符：\n"},{"attributes":{"class":"normal-img"},"insert":{"native-image":{"alt":"read-normal-img","url":"https://b1.sanwen.net/b_article/686db1c0cec063ac4a8392d31933d866085784bf.jpg","width":2000,"height":1200,"size":229422,"status":"loaded"}}},{"insert":"不管是几百hundred后都不加s，是因为这里的hundred不是名词，而是数词的一部分。\n"},{"attributes":{"class":"normal-img"},"insert":{"native-image":{"alt":"read-normal-img","url":"https://b1.sanwen.net/b_article/8b553211f3f29dacc709ae31990b43491b5f6eb4.jpg","width":2000,"height":1200,"size":300600,"status":"loaded"}}},{"insert":"几百几十几的话，只用把百用and和几十几连接起来就可以了。\n"},{"attributes":{"class":"normal-img"},"insert":{"native-image":{"alt":"read-normal-img","url":"https://b1.sanwen.net/b_article/9d5148db108675cd6f8ff9262bb5009ad928cb34.jpg","width":2000,"height":1200,"size":340937,"status":"loaded"}}},{"insert":"上千到上亿的表达，可以类比上百的表达：\n\n"},{"attributes":{"class":"normal-img"},"insert":{"native-image":{"alt":"read-normal-img","url":"https://b1.sanwen.net/b_article/f9c68ed7c1e3c40196c8b9857e5563754def36cd.jpg","width":2000,"height":1200,"size":338023,"status":"loaded"}}},{"insert":"英语是以三位来划分：\n"},{"attributes":{"class":"normal-img"},"insert":{"native-image":{"alt":"read-normal-img","url":"https://b1.sanwen.net/b_article/75b7db9fdc9cee5e96954835edaae1f01eb559df.jpg","width":2000,"height":1200,"size":300367,"status":"loaded"}}},{"insert":"写时以上的3546一般写成3,546，以方便阅读，这点和中文的万区分开来：\n"},{"attributes":{"class":"normal-img"},"insert":{"native-image":{"alt":"read-normal-img","url":"https://b1.sanwen.net/b_article/89094fe865e5f13949b2b24d2a698a1418c64b26.jpg","width":2000,"height":1200,"size":328647,"status":"loaded"}}},{"insert":"一个很大的数字，只要按三位划分成几段，从左侧开始，读出该段的数字以及之后的单位，再继续往右读下一段，如：\n478873467823按三位划分后为：478（其后单位为billion）,873(million),467(thousand),823\n读作：four hundred and seventy-eight billion eight hundred and seventy-three million four hundred and sixty-seven thousand eight hundred and twenty-three\n3.基数词可充当的句子成分\n基数词在句子中可以充当不同的成分，如：\nOne and two（主语）is three（表语）.\n一加二等于三\nIt costs fifty(Yuan).（做宾语）\n它要（花费）50元\nThere are two hundred（定语） sudents.\nYou two（相当于把you又说了一遍，同位语）can go with me.\n基数词还可以表示不确切的数量，比如成百上千，成千上万就可以说：\nhundreds of,thousands of,millions of\n这里的基数词用复数，加s，表示多个这样的计量单位，如：\nthousands of carrots数以千计（几千根）的胡萝卜\ntens of thousands of carrots数以万（多个”十个千“）计的胡萝卜\nhundreds of thousands of carrots\n几十万根胡萝卜\n4.序数词的构成形式\n1－19的序数词，大多直接在其后加”th“,如：\nseventh第7，thirteenth第13\n但是以下这些序数例外：\n"},{"attributes":{"class":"normal-img"},"insert":{"native-image":{"alt":"read-normal-img","url":"https://b1.sanwen.net/b_article/45251b14cebed8eae4db31f976d158430fd0007b.jpg","width":2000,"height":1200,"size":264600,"status":"loaded"}}},{"insert":"第20－第90(第整几十)\n\n\n"},{"attributes":{"class":"normal-img"},"insert":{"native-image":{"alt":"read-normal-img","url":"https://b1.sanwen.net/b_article/bb59da2fb82b908d0faa69f14b4b5c573c580a97.jpg","width":2000,"height":1200,"size":460350,"status":"loaded"}}},{"insert":"第几十几，第几百几十几：\n"},{"attributes":{"class":"normal-img"},"insert":{"native-image":{"alt":"read-normal-img","url":"https://b1.sanwen.net/b_article/5f5a0043d4ae693efad56f50e9364ce87c43fe71.jpg","width":2000,"height":1200,"size":331087,"status":"loaded"}}},{"insert":"这些序数词除了个位以外都是由基数词组成，个位则是十以内的序数词。\n5.序数词的缩写形式\n一般直接在阿拉伯数字后加th，如：\n7th,13th\n但也有例外，如：\nfirst→1st;\nsecond→2nd\nthird→3rd\n二十以上的序数词，则为：\n阿拉伯数字＋st/nd/rd\n21st,52nd,63rd,101st\n第11，第12，第13还是阿拉伯数字加th:\n11th,12th,13th\n6.序数词可以充当的句子成分\n主语：The fifth to pay the bill will get this prize.\n第五个付款的人将得到这个奖品。\n宾语：Please give me the second.\n请给我第二个。\nHe is the 13th person to fall over this morning.\n他是今天早上第13个摔倒的人了。\n表语：She was the fifth to pay the bill.\n她是第五个付款的人\n使用序数词时一般要加the，因为顺序知道了，多半是特指。\n但有的情况不能加the，不能乱加,如：\nThis is my first book.\n这是我的第一本书\n在序数词前有其他代词修饰book了，就表示这个名词已经被限定了，不能再加the.\n有些用基数词的表达和序数词相近，如：\nRoom 315\n315号房（第315的房间）\nPage 200\n第200页\nCatch-22\n第22条军规\n不过the second lesson（第二课）和Lesson 2（第二课）表面上都一样，但实际有差别：\nthe second lesson指的是第二节课，比如上了7节课，问第2节课上的什么时，用the second lesson；而Lesson 2更倾向于一门课程的第二课时，如数词分为基数词和序数词两个课时讲，这里的序数词用Lesson 2表达更合适。\n7.数词的用法\n①分数\n分数是由基数词和序数词共同组成的，分子用基数词，分母用序数词，如果分母大于1，分母的序数词需加s变成复数，如：\none third\n1/3\nthree fifths\n3/5\n另外，二分之一可以说成one second，也可以说成a half;四分之一可以说成one forth/a quarter；四分之三可以说成three fourths/three quarters.\n带分数，就是把整数和分数部分用and连接起来，如：\ntwo and one third二又三分之一\n②小数\npoint左边写基数词，point右边按顺序写个位基数词：\none point three four\n1.34\nzero point five seven\n0.57\ntwelve point eight nine six\n12.896\n③百分数\n就是基数词后接百分号，如：\ntwenty-five percent\n25％\ntwo point five percent\n2.5%\n④倍数\n表倍数一般使用half,twice,three times这样的词，再搭配固定的表达，如：\n倍数＋the +计量＋of：This carrot is half/twice/three times the size of that one.\n这根胡萝卜是那根的一半/两倍/三倍大小。\n倍数＋as...as...：\nI have half/twice/three times as many carrots as he has.\n我有的胡萝卜是他有的一半/两倍/三倍\n倍数＋比较级＋than:I can eat three times faster than he can.\n我吃东西的速度比他快三倍。\nby＋倍数：I have increased my income by three times.\n我增加了三倍收入。\n⑤数字符号和算术\n2 plus 2 is 4\n2+2=4\n4 minus 2 is 2\n4-2=2\n2 multiplied by/times 3 is 6.\n2×3=6\n8 divided by 4 is 2\n8÷4=2\n2 squared is 4\n2²＝4\n2 cubed is 8\n2³=8\n4 is more than 3\n4＞3\n2 is less than 3.\n2＜3\n⑥单位\n时间\nat seven\n7:00\na quarter past seven/seven fifteen\n7:15\nhalf past seven\n7:30\nten to eight/seven fifty\n7:50\n一般情况下，半点之前用past表示；半点之后用to表示，表差几分到几点\n日期\n英式：日/月/年，如：\n12th December 2020\n2020年12月12日\n美式：月/日/年\nDecember 12th 2020\n日的表达是序数词，表某个月的第几天，读时要把the读出来。\n500 B.C.(英语before Christ,“基督前”)\n公元前500年\n500 A.D.（公元500年，拉丁语Anno Domini，“主的年份”）\n2020（可以不加A.D.）\n公元2020年\n2020‘s/2020s\n21世纪20年代\n1980's/1980s\n20世纪80年代\n长度\n长：long(adj.)/length(n.)\n宽：wide(adj.)/width(n.)\n高：high(adj.)/height(n.)\n例句：\n基数词＋单位词（复数）＋形容词（长宽高）：\nThe river is 1000 meters long.\n这条河有1000m长\n基数词＋单位词（复数）＋in＋名词（长宽高）：\nThe river is 1000 meters in length.\nThis room is 20 by 35 meters.\n这个房间是20米×35米。\n面积的单位是square meters.如：\nThis room is 700 suqare meters.\n这个房间有700平方米。\nThis box is 8 by 5 by 6 centimeters.\n这个盒子的长宽高分别是8厘米，5厘米和6厘米。\n温度\n37 degrees centigrade/Celsius\n37℃\n37 degrees Fahrenheit\n37℉\n10 degrees below zero\n-10°(当大家都知道单位是摄氏度的情况下，可以省略centigrade/Celsius)\n"},{"attributes":{"class":"normal-img"},"insert":{"native-image":{"alt":"read-normal-img","url":"https://b1.sanwen.net/b_article/f9b8737c64c1597440db9295577c85efbd2c298d.jpg","width":2000,"height":1200,"size":327371,"status":"loaded"}}},{"insert":"\n"}]}
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