一般來說,城堡是巨大的建筑物,需要打下夯實的地基并且使用石頭等材料。
If the foundations are not strong enough, the castle could collapse.
如果地基打的不夠堅實,城堡就會倒塌的。
The idea of building a castle in the air-with no foundation at all-is, of course, ridiculous.
在空中建城堡,不打地基,當然可笑至極。
That is why this idiom is used to describe ideas that are not realistic, as if they are dreams orfantasies.
這就是為什么這個習(xí)語是用來描述那些不切實際的想法,就像夢跟幻覺一樣。
So when someone describes a plan or course of action that we believe may be impossible toachieve, we tell him, "You're building castles in the air."
當我們覺得某人描述的計劃或者行動方案是不太可能完成的,我們會告訴他“你是在空中蓋城堡。”
A similar idiom is "building castles in the sand."
一則類似的諺語是“沙堆上壘城堡”。
We know that, on a beach, sand castles are inevitably and easily destroyed by the tide.
我們都知道,在海灘上,沙堆城堡不可避免地很容易就會被海浪破壞掉。
They are not built to last a long time.
它們不會維持很長時間。
So when we say someone is "building castles in the sand," we mean they are creatingsomething that won't endure very long.
所以說當我們對別人說“沙堆上壘城堡”,我們的意思是他們建成的東西通常是堅持不了多久的。