周某

急需从化学中的获得人生感悟或哲理 1._____ used to be thought that the earth was square.A.There B.It C.What D.That为什么选B不选A?不是there be句型吗?2.The teacher wants ____ student to succeed.However,not ___ can findhis or her way to success.A.every;each B.each;each C.each; 将NaOH溶液与NH4Cl溶液混合生成NH3·H2O，从而验证NaOH的碱性大于NH3·H2O，继而可以验证Na的金属性大于N，你认为此设计是否合理？并说明理由 已知F1,F2是椭圆的两个焦点,P为椭圆上一点,角F1PF2=60.求1.椭圆离心率的取值范围2.求证：三角形F1PF2的面积只与椭圆短轴长有关. 实验室中有一包由氧化铜（CuO）和另一物质组成的混合物,测得此混合物中氧元素的质量分数为34%,则此混合物中“另一物质”可能是下列物质的：A:氧化镁MgO B氧化钠Nn2(角码）O C氧化铁Fe2(角 说出理由由C H 构成的化合物叫_____那么CH4C2H2C2H6C8H8叫什么 两道化学题(说出理由)1下列物质的PH大于7的是( )A食醋 B胃酸 C石灰水 D汽水(说出理由)2稀硫酸和下列物质既能发生中和反应,又能产生白色沉淀的是( )A氢氧化镁 B氯化钡 C碳酸钡 D氢氧化钡(说出 化学选择,说出每个选项的理由下列图象能正确反映其对应操作中各量变化关系的是A．向二氧化锰不断加入过氧化氢溶液 B．向一定温度下的饱和氢氧化钙溶液中不断加入氧化钙固体 能说说理由就更好了Can you make sure _________ the gold ring?A.Where Alice had putB.Where had Alice putC.Where Alive has putD.Where has Alice putWord came ________ his poem won the first prize.A.thatB.whetherC.asD.becauseI remember ______ thi （1）There is _____ water _____ air in space.A.not;or B.no;and C.no;or D.not;and(2)Class Two students will have a ______ of geography.A.knowledge B.study C.idea D.way(3)I think she ______ about her lessons.A.need't worry B.doesn't need worry C.need 1:There is ____ water in the cup.A:lot of B:many C:a little D:a few2:Millie ____eating fruit ____ apples,oranges and pears.A:likes,like B:like,likes C:like like D:likes likes 一道化学问题,各位帮忙解答,谢啦在标准状况下,某气态烃112ML,完全燃烧后生成二氧化碳和水蒸气的体积比是3：4,把燃烧产物通过碱石灰,碱石灰质量增加1.02g,求气态烃的分子式（请详细解答） 1:Learning English isn,t diffvult!In fact there,s nothing _____itA:for B:to C:at D:in2:Are you good ____remembering English words?A:to B:for C:in D:at3:Jenny loves sports and she,s particularly been ___tennis and athletics.A:at B:on C:over D:in 4:The 在相同的温度和压强下,不同气体分子间平均距离是相等的,那么相同体积的不同气体中含有分子数是否相等?为什么 F1,F2是椭圆的两个焦点,若椭圆上存在点P,使角F1PF2=120°,则离心率求详解斜率怎么算得 已知F1,F2是椭圆的两个焦点,P为椭圆上一点,∠F1PF2=60°求椭圆离心率用向量怎么做 已知F1、F2是椭圆的2个焦点,P为椭圆上的一点,角F1PF2=60度,求e的范围? 1.At what number will the general manager ____________ that call?A.turn back B.return C.phone back D.give back 2.For further information,please ____________ 54362163,extension 205.A.get in touch B.communicate C.contact with D.contact 3.In spring peop 1）Can you help me _____ my English?A.with B.of C.learning D.about2）Bob can play ____ tennis but he can't play _____ violin.A.the,the B./,/ C.the,/ D./,the3）Do you often go to ____ football games _____your friends?A.see,and B.look at,with C.watc 已知F1,F2为椭圆的焦点,P为椭圆上任意一点,∠F1PF2=45°1 求椭圆离心率的 取值范围2 求证：三角行 F1PF2 的面积 只与 椭圆的短轴长 有关为什么我的（1）算出了一个很夸张的数字,还有一个无解 已知F1,F2为椭圆x^2/100+y^2/b^2=1（0＜b＜10）的左右焦点,P是椭圆上一点.若∠F1PF2=60°且△F1PF2的面积为64√3/3,求b的值? 氯气有毒,为什么还可以用来消毒? The doctor knew how to____an emergency like this.\x05A.deal in B.settle with C.act on D.cope with2.It is wrong to___a person of a crime unless you have proof that he is guilty.blame B.accuse C.charge D.warn 3.The repairman examined car engine ____but 求答几道英语选择题 设F1,F2是椭圆的两个焦点,若椭圆上存在点P,使角F1PF2等于120度,则椭圆的离心率e的取值范围是多少? 已知F1,F2是椭圆的两个焦点,P为椭圆上一点,若角F1PF2=90度,求椭圆离心率的取值范围我自己算了一下 是用的余弦定理来表示写的可是是错的 能不能用余弦的那种方法写一写 非常感谢@@@@@!它到 求答 这道英语选择题怎么答?In my opinion,all our teacher()good to us students at present.He is very strict with us.A.does does does B.does do doC.does does do D.did do does并请解释一下原因 1.Both Japanese and French are now to me.I don’t know ______ of them.A both B all C either D any2.There are many trees ______ of the road!And ______of the trees is growing larger and larger.A on both side;a number B on each sides; a number C on bot 已知椭圆的两个焦点坐标分别是F1(-4,0),F2(4,0),椭圆的弦AB过点F1,且三角形ABF2的周长为20.求椭圆的标准方 已知F1、F2是椭圆x^2/a^2+y^2/b^2=1(a>b>0)的两个焦点,AB为过F1的弦,则三角形ABF2的周长是 2道化学问题（并说明理由）1.生活中常见的下列现象,发生化学变化的是A.冰雪融化 B.生米煮成熟饭 C.湿衣服晾干 D.玻璃杯炸裂2.常温常压下,不适宜用物理性质区别的物质组是A.酒精和食醋 B.