陆地淡水元素浓度

甲 乙两人同时骑自行车从相距S千米的两地同时出发,若同向而行,甲经过a小时追上乙,若相向而行,经过b小时两人相遇,设甲速为v1千米/小时,乙速为V2千米/小时,那么V1/V2=___ 军训总结怎么写啊要朴实一点的,不要语言太过华美的,能表现出高中生的心路历程就行 怎么写军训总结 What's happened to my Library books?___________A:I've no idea B:you bought them yesterday.C:you bought them yesterday D:They're about long life. 已知直线l被两条直线：3x+y-6=0和3x+y+3=0所截的线段长为3,且过点（1,0）,求直线l的方程 What a pity it is to find so many books with pages-----in our library!A missed B lose C losingD missing 选哪个,为什么这么选, 已知直线l被两平行直线3x+y-6=0和3x+y+3=0所截得的线段长为3,且直线过点（1,0）,求直线l的方程答案一定要详细 直线L过点A(1,O),且被两条平行直线3x+y-d=0和3x+y+3=O所截得的线段长为9,求直线L的方程. 已知直线l被两平行直线3x+y-6=0和3x+y+3=0所截得的线段长为3,且直线过点(1,0),求直线l方程 Mr Smith asked ____off because he didn't feel well.A.three day B.three days C.three days' D.three-day为什么答案是B,不是选D作形容词吗? 记到语文选择题 请求高人呢解答 实在搞不懂,望指教No one but her parents _______ about ita)knows b)know c)is knowing d)are knowing我的选择是B,"her parents"难道不是应用谓语的复数形式吗?是答案错了还是另有语法规则?望达人指教No one but...but 5/17X5/12X17 2（简便计算） 7/13+7/13X12 （简便计算） 大智慧的预警公式改为通信达的预警公式DYNAINFO(14)>-2% and DYNAINFO(14)2 andDYNAINFO(41)/DYNAINFO(43)>2 and DYNAINFO(48)/DYNAINFO(50)>2 and DYNAINFO(26)>1000and DYNAINFO(27)>1000 and DYNAINFO(41)>1000 and DYNAINFO(48)>1000; 6/17x5/13-5/17x6/13 简便计算 Don't talk loudly in public,_ _.(反意).谁告诉下 Don't talk loudly in the hallways.的汉译 department和section有什么区别?English departmentdepartment storewhat section will you be working in? DIVISION AND DEPARTMENT请问division 和department那个的范围大,有什么区别? buyer/purchaser/sourcer section/department/division这两组单词用法上的区别这两组单词在公司里用法有什么讲究的,所用的范围 八分之五比九分之五化简比是几比几? 八分之三：九分之四如何化简比?写出过程~~ 1又4分之1：八分之五（化简比） Don't talk and your friends in the library.改错 A SHORT HISTORY OF THE WORLD怎么样 quite a nice cup 还是 a quite nice cup 把0.128比八分之五化简. Division和departmen区别?都是部门的意思,哪个范围更大? A MONETARY HISTORY OF THE UNITED STATES 1867 1960怎么样 英语翻译Most emigrants escaped political oppression,to seek the freedom to practice their religion,or for adventure and opportunities Settlers including English,Dutch,Swedes and Germans,a few French and a scattering of Spaniards,Italians and Port (高一)关于不等式组的题目关于X的不等式组x²-x-6>0 2x²+(7+2a)x+7a