5 year green card中,为何year不是复数形式?求教了!

5 year green card中,为何year不是复数形式?求教了! 选择.Let's buy a _____for our gyandparents.A.New Year Card B.new year card C.New Year card make a new year card的意思 Mr Green goes to America by plane every year对划线部分提问every year为划线部分 对划线部分提问 Mr Green will move to Shanghai in a year -----------in a year 为划线部分 Mr.Green goes to America by plane every year. every year划线Mr Green goes to America by plane every year对划线部分提问every year为划线部分 雅思剑5 test4中section1 答案为one year 填 a year 英国绿卡用英语怎么说?UK green card? Mr green f() to England every year 有限集合S中元素的个数记作card（S）,A⊆B的必要条件是card（A）≤card（B)为什么是真命题card（A）≤card（B)可以推出A⊆B 我认为不正确card（S）不是表示元素个数吗?A=｛0.1.｝B=｛5.6.7｝它 有限集合S中元素的个数记作card(S),设A,B都为有限集合,给出下列命题:(1)A∩B=空集的充要条件是card(A∪B)=card(A)+card(B);(2)A包含于B的充要条件是card(A)≤card(B);(3)A并B的充要条件是card(A)≤card(B);(4)A=B 有限集合S中元素的个数记作card(S),设A,B都为有限集合,给出下列命题:(1)A∩B=空集的充要条件是card(A∪B)=card(A)+card(B);(2)A包含于B的充要条件是card(A)≤card(B);(3)A并B的充要条件是card(A)≤card(B);(4)A=B 制做一张新年贺卡的英文应该是make a New Year card还是make a New Year's card? christmas card now ycar card post card identity card guest card bank card的意思回答对后给5分 the tree is green all the year ___怎么填 in defence Mr Green stood up in defence of the 16-year-old boy,saying that he was not the one to blame.中in defence of 请造个句! 改为同义句：Mr Green goes to America by plane every year.Mr Green .America every year. card这个符号在数学中是什么意思?