众所周知，钻石是最坚硬的物质。的翻译：As we all know that diamonds are the hardest substance. 什么意思？中文翻译英文，英文翻译中文，怎么说？

青云英语翻译

As we all know, diamonds are the hardest substances.

As we all know that diamonds are the hardest substance.

It is well known, the diamond is the hardest material.

It is well known that diamond is the hardest material.

As we all know that diamonds are the hardest substance.