A:16-6=10
B:16-10=6
C:6+10=16
D:10+6=16
— Jack, what would you like to eat now?
— Oh, mom. I don't feel like ________ anything now. I'm so tired.
心室收缩时,心脏内的瓣膜的情况是
已知,如图,A是⊙O外一点,AB,AC分别与⊙O相切于点B,C,P是BC上任意一点,过点P作⊙O的切线,交AB于点M,交AC于点N,设AO=d,BO=r.求证:△AMN的周长是一个定值,并求出这个定值.