plain water

基本解释

But you can’t coat yourself with plain water because it just runs off.
但是很明顯，你竝不能簡單的在身上塗一層水，因爲這很容易揮發。
I also include a paintbrush and a lidded container with plain water in it for magic painting.
我還放了一個毛筆和一個裝有水的帶蓋子的容器，它們是用來畫魔術畫的。
The Mars lander, by contrast, would visit a place where the seas — plain water in this case — vanished long ago.
與之相比，火星著陸器將會拜訪一個淡水（如果有水存在的話）早已消失的地方。

Okay, how little plain water was actually consumed.
好,所喝的白開水很少
耶魯公開課 - 關於食物的心理學、生物學和政治學課程節選

To truly stay well hydrated, you likely have to drink more coconut water, than if you drink plain water.
FORBES: The Truth Behind The Coconut Water Craze
The bottom line is that most people who lightly exercise do not need sports drinks or even coconut water- plain water is just fine.
FORBES: The Truth Behind The Coconut Water Craze
While coconut water is low in calories, rich in potassium, and fat and cholesterol free, the evidence that it is actually better than plain water for simple hydration is unfortunately lacking.
FORBES: The Truth Behind The Coconut Water Craze