题干
— What a nice motorbike! _________ have you been on it?
— Just to Beijing.
A：How long
B：How soon
C：How far
D：How often
答案(点此获取答案解析）
C
,则三棱锥P-ABC的侧面积的最大值为
若
与
异面,且
异面,则（ ）