In the presence of this ligand, this molecule, it's open, it allows transport of this ion, when the ligand is gone it doesn't.

配体存在的情况下通道才打开,允许这些离子穿过,配体离开后,这些离子就不能通过了

耶鲁公开课 - 生物医学工程探索课程节选

Even better, when you remove it, it's gone.

CNN: module

"In normal speeds it's gone in seconds, but in slow motion, when you see it lasting 40 seconds to a minute, you get a real sense of the beauty, the scale and the size and power of that shot which is exactly what we wanted, " Fothergill said.

CNN: 'Earth' takes viewers on 'breathtaking' global journey

And they thought they had taken the lead after 10 minutes when Blackstock's header looked as though it may have gone in despite the efforts of Dean Kiely.

BBC: QPR 0-2 West Brom