In seven innings, he gave up only four hits and two earned runs against the Pittsburgh Pirates.

VOA: special.2010.06.18

So you get two answers when it hits the ground.

解出了两个落地时间

耶鲁公开课 - 基础物理课程节选

So you get two answers when it hits the ground.

解出了两个落地时间

耶鲁公开课 - 基础物理课程节选