In two thousand eight Norway opened a so-called doomsday vault designed to be secure from any threat -- even an asteroid strike.

VOA: special.2010.08.24

However, when that gate is opened, the sodium channel is now going to be incredibly selective and only let through sodium ions and no other type of ion.

但是，当闸门打开的时候，钠离子通道,将会有极高的选择性,不允许除钠离子以外的任何其它离子通过。

麻省理工公开课 - 化学原理课程节选

Should the new territories be opened or closed to slavery.

VOA: special.2009.02.26