Instead of passing water molecules, these membranes pass ions.
跟让水份子通过不同的是，这些过滤膜让离子通过。
2
I pass the bottled water - with stainless steel water bottles for each member of my family, I wouldn't think of wasting money on bottled water.
我越过瓶装水——每个家庭成员一个不锈钢水杯，我不用浪费钱在瓶装水上了。
3
The membrane’s protein channels, each just a few nanometers across, allow a stream ofwater molecules—and only water molecules—to pass single file at a rate of one billion per second.