题干
We can't work out the physics problem. Can you tell us________?
A：how to do
B：what to do it
C：how to do it
D：what should to do
答案(点此获取答案解析）
C
We can't work out the physics problem. Can you tell us________?
A：how to do
B：what to do it
C：how to do it
D：what should to do
上的一点,且AC=4,BC=3,则☉O的半径r等于（ ） 