a+(-b)+c(-d)是_____,_______,______,_______,的和,可以省略括号,加号和的形式为——————————.快

13.Forty dollars _ _ enough for a child .13.Forty dollars _____ enough for a child .A.are B.is C.be D.am 对划线部分改错let's buy things to a birthday party._____ _________ _ ________________A B C D 1.The Smiths _____ at home now.A.is B.are C.can D.does2.我想要两条牛仔裤.I'd like _____ _____ _____ _____.请告诉我为什么,O(∩_∩)谢啦! 用代数法化简逻辑函数_ _ _ _ _F=A B C +A B + A D + C+B D过程麻烦的话就答案也行,实在是太感谢了 如图所示,B和C两点把线段AD分成2:3:4三部,M是AD的中点,CD=8,那么MC的长是多少?|____|_____|_|________|A B MC D 如图所示,B和C两点把线段AD分成2:3:4三部,M是AD的中点,AD=8,那么MC的长是多少?|____|_____|_|________|A B MC D Have you _____ learned English?-Yes,I’ve _ ___ learned a lot.A.never,ever B.ever,never C.ever,already D.already,ever 第三题a b c d分别解释.>_ (a-b)-(c+d)去括号形式详细原因%>_ 一、有一种无色气体A,它不能燃烧,也不支持燃烧.A溶于水生成B,B能使紫色石蕊溶液变成红色.B不稳定,能分解出C和气体A.气体A能使澄清石灰水变浑浊,生成白色沉淀D.(1)推断:A是_____ B是_______ C是_ _____ pandas are very shy ,_______ please be quiet .A.because_soB.because_/C./_/D.so_/ 9.This farm tool needs _.A.repair B.to repair C.repairing D.repairs 说明原因The little boy is dirty from head to foot because he _____ in the mud all morning.A has played B is playing C has been playing D was playing 为什么答案是C不是A 若a-b=-3,c+d=2,则（b+c）-(a-d)的值（ ） a.-1 b.-5 c.5 d.1______|____|_|_____|___________________C 0 b a有理数abc在数轴上的位置如图,化简|c-b|+|a-c|+|b-c| 若a-b=-3,c-d=2,则（b+c）-(a-d)的值（ ） a.-1 b.-5 c.5 d.1______|____|_|_____|___________________C 0 b a有理数abc在数轴上的位置如图,化简|c-b|+|a-c|+|b-c| A、B、C、D、E、F是中学化学中常见的物质其中A、B为单质,F为白色沉淀,D为气体.（1）若D的水溶液显弱酸性,则A是_____,B是______,C是______,D是_____,E是_____,F是_____.（2）若D的水溶液显碱性,则A是_____, Could _ have been _ who helped Sunny get her work done?A.they ,it B.they ,them C.it,them D.it,they 答案是 D为啥? 1.Did you go to the dinner party?—No,I _.A.didn’t invite B.wasn’t invited C.wasn't invited D.haven't invited2.Would you like to go fishing with me?-----_____,but I am very busy at present.A.I'd love to B.I think so C.I'm第一题C是am not invi 有一道英语单选题,题干是：A _ and _ has been bought for you.Which is wrong?选项是：A) gold watch ;chain B )knife ;fork C)pen;pencil D)desk; chair 应该先哪个?为什么?题干是：A ____ and _____ has been bought for you.Which is w