Vaction variable
[机] 作用变数
🧩 词语组成解析
🗣️ 情景例句
Do we have to pre-book tours, or can we get them on site?
我们必须预定行程， 还是到那个地方再说？
We never know the worth (or value) of water till the well is dry.
井枯方知水可贵。
Although we can't see these atoms, they really do exist.
虽然我们看不见原子，但它们的确存在。