____ some ways, his classmates are all kind ____ him .
A: By, of
B:On, with
C:In, to
D:Of, by
欣欣水果店运来26箱苹果和18箱梨,要想算出运来的这些水果一共有多少千克,我们还需要知道哪些信息,请你写出来:____ .
△ABC中,∠C=90°,AC=6,BC=8,△ABC的外接圆半径为R,内切圆半径为r,则R与r的比值是( )