Knowing what he is capable of, you have every right to be afraid.
既然你知道他的能力如何,你的担心是完全可以理解的。
With the invention of writing, a great advance was made, for knowledge could then be not only communicated but also stored.
随着书写的发明,又迈进了一大步,因为这样一来,知识不仅能交流,而且能储存了。