人人都说水是透明的。可是，其实只有薄层的水才是透明的。海洋的底层是漆黑的，因为阳光不能透过那么厚层的水。而且不只是水——所有的物质取一薄层都是透明的，厚层的就不透明。比如取一块无色透明的玻璃，从它的边线去看它，你看那玻璃也就不是无色透明的了。不久以前 Everyone says that water is transparent. However, only thin layers of water are actually transparent. The bottom of the ocean is dark, because the sun cannot pass through that thick layer of water. And it’s not just water - all thin layers of material are transparent, and thick layers are opaque. For example, take a piece of colorless and transparent glass and look at it from its edge. You see that the glass is not colorless and transparent. not long ago