Peter ________ some beautiful postcards to his friends yesterday.
A:gave
B:bought
C:made
D:chose
已知点P到⊙O的最近距离是3cm、最远距离是7cm,则此圆的半径是____cm 。若点P到⊙O有切线,那么切线长是____
I found a little boy in the street on my way home.