怎么判断物质显酸性或碱性?

几道有理数计算题,（1）—2—（—3）+(—8） （2）（—12）÷4乘以（—6）÷2 （3）（—24）乘以（3分之2+4分之3—8分之7 （4）（—4）÷（3分之4）乘以2+（—1）的2010次方 乘以（—6） 几道有理数计算题, 高二英语题一道the english book has been simplified to make it eaiser to understand,为什么不是to be understood~?被动 高二英语,第一题 甲数的平方比乙数的平方多28求甲乙数 甲乙两数的比是4:3,两数的和是28,甲数是（）,乙数是（） 求解图上的两道题,要有过程,高一数学必修一的, Many people ____-on the upper floors when the ire broke out .Fortunatelyly,they wre rescued.A.were to get trapped B got grapped C would get trapped D get to trap it was in the cinema ,three blocks away,where Avatar was on.里面的where用法对吗.was on 后面缺宾语,应该用which才对啊?可是答案是where.为什么?我知道 three blocks away,是插入语 我是问was on 后面缺成分为什么要 5/17+5/9-1/6+12/17简便方法 请不要乱回答,我是很认真再问这个问题 A宪章运动的兴起 B1382年议会改革 C”光荣革命“的爆发 D责任内阁制的形成 .这4个的性质有什么不同?怎样区别? 【一道题】【高二英语-模块6】Everybody in our hometown ,men and women ,young and old ,______sports and games.A.are fond ofB.joinsC.enjoysD.go in for请给出正确答案并说明理由. 关于x的方程2ax^2+(8a+1)x+8a=0有实根,求a取值范围 1 On the _____,I saw a bottle of apple juice,bought by mother as my little brother's birthday gift.A kitchen's table B kitchen table 为什么呢?2 _____ to play basketball together with your best friends on a cool fine afternoon!A How fun B What fun 1】sometimes it was a bit boring to work there because there wasn't always _____much to do.A.such B.that C.more D.very (为什么选B?）2】it is said in the book that Thomos Edsion_____the word leading inventor for sixty years.A.would be B.has bee 各位仁兄大姐,我星期天就要英语竞赛了,谁能告诉我英语竞赛怎么复习,给我点题也行呀,ps：复赛.+哪里有高考英语的听力呀,愁死我了. 某宾馆有3人房间和2人房间共20间,总共可以住旅游客48人,则该宾馆有{ } A .3人房4间,2人房间16间 B.3人房间12间,2人房间8间C.3人房间8间,2人房间12间D.3人房间10间,2人房间10间 求英语作文啊!假如星期天是你妈妈的生日,你想对她说什么?急 平方得64分之25的数为什么急 一个数的平方的倒数为36分之二十五,求这个数? ______ from his appearance ,he looks like a teacherA judged B judgingC To judgeD judge有这样一句话,After writing the letter ,l listen to the music for a while这句话老师算我错的,如果从现在分词角度,这应该是对的,如果没 Rose was wild with joy ---the result of the examination.A.toB.atC.byD.as答案上为什么是B？ The food and Agriculture Organaization of the UN says more than forty billion dollars a year needs to be invested in agriculture to_______ world hunger,which is becoming more and more serious.A.defeat B.cure C.reject D.instruct the new school library_____over there now will be put into use next term为什么填being built 而不是built?没有now就可以了是不 1._____________,she doesn’t get up without her mother’s help every morning.　　A As she is a teenage B As she is teenage C A teenage as she is D Teenage as she is2.Only by chance _____________where the food was stored.A.Mary discovered B,Mary d 12分之5的分母增加12,分子不变,分子应增加( ) 在表格中怎么找中位数比如人 数：1 1 2 6 3 2加工的个数:540 450 300 240 210 120 这组数据中的中位数是多少? 在cad中,实际比例=图形比例*打印比例 CAD块中的位置、比例和旋转角度各代表什么意思! 怎么在表格中找中位数比如人 数：1 1 2 6 3 2加工的个数:540 450 300 240 210 120 这组数据中的中位数是多少? 表格里的怎样求中位数,列式,