etch off造句

例句与造句

1. This usually does nothing for stains, but will etch off a very thin layer of concrete, possibly taking the stains with it.
2. The gases always include a carbon source, typically methane, and hydrogen with a typical ratio of 1 : 99 . Hydrogen is essential because it selectively etches off non-diamond carbon.
3. It's difficult to find etch off in a sentence. 用etch off造句挺难的