一道英语题
______you read through these two books you would surely make great progress in both grammer and vocabulary 为何选If only而不选Only if
答：If you had studied hard, you would have made great progress. 是一句对过去的虚拟的句子详情>>
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>>
