,下题我知道选B ,但是不明白为什么,The watch ------ unticed for several days before i found it.A had laid B had lain C had been laying D had been lain

,下题我知道选B ,但是不明白为什么,The watch ------ unticed for several days before i found it.A had laid B had lain C had been laying D had been lain 我不明白59题,为什么选b July is the month < > is usually the hottest.A,whose weather.B,when the wheather 为什么答案不选A.我知道B对着，但是我不明白这个月的天气 为什么不属于所属关系。 ∫（上b下a)f(x)dx-∫（上b下a)f(a+b-x)dx=?如题正解中用a+b-x=t代换然后,然后∫（上b下a)f(a+b-x)dx变成∫（上a下b)f(t)*(-1)dt我不明白的是咋变成上a下b了,-t我知道我最主要的是问上下限怎么变的?我知 以上 我知道答案选B 但是我不明白CE2=AB·CF 为什么是正确这貌似是一道基础题 但是我学的不好 以及涉及知识点=V=非常感谢 2013上海市虹口区高三英语一模的一道语法题35.It worries the couple a lot ______ their only son is behaving worse and worse these days.A.how B.why C.that D.what我知道答案选C,也知道为什么选C.但是我不明白为什么不 I___you not to move my dictionary ----now I can't find it.A.asked B.ask C.was asking D.had asked答案选的是A,但是我不明白为什么不能用现在完成时 It's long time since he left his English,____?[A] didn't he[B] hadn't he[C] wasn't it[D] isn't it我不知道是怎么判断的,这题应该是反意疑问句.但是我不明白的是这里.就是带从句的反意疑问句,那逗号后面的结尾 Tom doesn't have to be made ____.He is always a hard-working studnet.A：to studyB：studying这题我知道应该选A.但是B,为什么不行?动词ing形势是可以做宾补的.问下：The teacher doesn't have to make Tom to study.The teacher doe 不明白为什么选B,我不知道怎么判断D错了问题链接在上面.打错了是地理题 The door_ ．Better have it repaired． A．won’t shut B．hasn’t been shut C．won’t be shut D．isn答案选A。我也知道，但是为什么用won't 回收站.BIN和Recycled有什么区别?每个分区下有两个隐藏的MS回收站的图标,但是名字不一要,里面内容也一样.虽然我知道它们是回收站,但不明白为什么有两个? i'd rather you _____ these important documents with you .A.hadn't taken B.won't take C.didn't take D. not take我知道答案可以选C,但是为什么A不行? 请教英语考试题这两道题我做错了,但是不还是有些不明白,我知道正确答案,但是不知道其中的原因,请学长解析,选择：Mary wants to know what she_______when she wears the new coat（此题应该选A,我选的是B i·d rather you__anything about it for the time being.A.do B.didn·t do C.don·t D .didn·t请问选哪个?我想知道理由.而且,我不明白最后为什么be会有ing 换元法中,比如f(x+1)=x,求f(x)的解析式,在过程中设X+1=t,t=X+1,X=t-1,f(t)=t-1,则f(x)=x-1做题我知道过程咋做,但是不明白具体过程怎么变得,我搞不明白这些X之间的关系,和X和t的关系,谁能告诉我这些字 △abc的三边关系为a4+b²c²-b4+a²c²=0,求三角形形状.（a4表示a的四次方）我知道正确答案,但是不明白为什么不是等边三角形? He lived in London for 3 years,during _________ time he learned some English.A.this B.which C.that D.same 我知道选B,但是我不明白为什么横线后面后有个单词time 怎么解释during which timeIs this just the city_________ the