正定矩阵行列式大于0

I have 1.87 （ ） A.dollar B.dollars director of admission是什么意思 associate account director是什么意思 board of director是什么意思 Always For You翻译成中文是什么意思? Welcome to my space翻译成中文是什么意思? I have three ___notes in my pocket.A five dollar's Bfive dollars两者的区别,该选哪个，为什么选那个先项？并说明理由 BSc at Chinese university 这里的BSc是什么意思. 用near behind beside under 等词各写一句话. 用left,next to,near,behind,beside造句,一个单词造一句 near是什么词 Are you not 和Aren't you?什么区别 根据上下文及首字母提示填空 We have many festivals in a year .(1)J------is New Year”s Day.Women“s根据上下文及首字母提示填空We have many festivals in a year .(1)J------is New Year”s Day.Women“s Day is on March（2）e- Children May New Year Christmas Women National AprilFool TreePlanting 的中文意思 希特勒为何如此强大他是如何做到的 伟大的希特勒所做的事无可厚非他要带领德国走向繁荣 并为世人瞩目 You should never go back for anything you have left on the bus or bend down near or under the bus. Try Again,Never Stop Believing...When you fall down,Just Try Again!这句话是什么意思? business development director or manager 这个职位,的工作职责是什么?主要工作内容是什么? Director和senior manager哪个级别高 有关氨基酸的知识 怎么知道氨基和羧基的个数 怎样知道氨基酸的羧基、氨基?救 All of the memories,so close to me,just fade away . He spend an hour working out the math problem.的意思和同义句 i am the red in the roses,the flowers .i am the green ...是哪首歌的歌词 __do you ___about spring?---The flowers and the green trees.Awhat ;like Bwhat ;think 那么这里面how/what dou you think /like ..还有how so you do what do you do 等这些具体的句型是什么呢?有哪些用法呢? The family _____had lost everything in a big fire got much help from their f这里的 family 是整体的意思还是成员的意思 用 who 还是whichfriends. accrual accounting是什么意思 but its population is small,which is only about 20 m___ 改错The People's Republic of China was foung on Oct.1,1949. ___on Oct 1 st,1949, the people Republic of China celebrated her 60thbirthday on Oct 1st last year.A.Built B.Founded C.Established D. Created请解析 Chen Qiang told Mr Smith that the People's Republic of China was founded on Oct.1st,1949为什么用was founded 而不是has founded?不应该只是过去的过去吗?错了，为什么不是has been founded?