单项选择
18. -- __________ will you stay there? -- for a week. i'll be back __________ seven days. a.how soon, in b.how long, for c.how soon, for d. how long, in
答：1.She remembered she ________ the book. c.hadn't paid for 她记得他还没有付书的钱。“表达截止到过去某...详情>>
问：已知a,b属于R,求证:a^2+b^2>=a*b+a+b-1
答：答案如下： 由（a-1)^2+(b-1)^2>=0 得到a^2+b^2+2>=2(a+b)--------(1) 又由(a+1)^2+(b+1)^2>=2(a+...详情>>
问：“ prefer to...rather than ”是一个词组吗？
答：prefer to do rather than do sth 与其作后者的事情的不如做前者去事情。 可以等同于= prefer to do instead o...详情>>
