(Speaking) But a study at the University of California Berkeley found that 3-D movies can cause eye strain.

VOA: standard.2010.02.21

Now you have to know from elementary calculus that v times dv/dt is really d by dt of v square over 2.

根据初等微积分知识你们得知道,v乘以dv/dt其实就是d/2)/dt

耶鲁公开课 - 基础物理课程节选

(He recalls his emotion as he stepped back onto U.S.soil."It felt great." as his voice quivers.) "I thought I'd never be able to come back."

VOA: standard.2010.06.22