"This change to a higher phase of alert is a signal to governments, to ministries of health and other ministries, to the pharmaceutical industry and the business community that certain actions should now be undertaken with increased urgency, and at an accelerated pace,"

VOA: standard.2009.04.29

Most frequently, chord changes come on the downbeat so composers signal to us in a fourth way the downbeat by means of chord change.

通常,和弦的变化都在重拍上,所以作曲家们用这第四种途径,通过和弦的变化告诉我们重拍的位置

耶鲁公开课 - 聆听音乐课程节选

It sends it's signal, it's signal - the signal that it sends is this change in voltage, and once it changes, maybe it's all done.

它发出信号,它通过电压的改变发出信号,然而一旦电压改变,细胞的使命到此就终结了

耶鲁公开课 - 生物医学工程探索课程节选

When they receive the signal they make - they change in a very specific way and the cell can recognize this change that's occurred at the cell surface.

当它们接收到信号之后,就会发生十分特殊的变化,细胞能够识别自身表面发生的这种变化

耶鲁公开课 - 生物医学工程探索课程节选