Bow, string, and arrow already constitute a very complex instrument, whose invention implies long, accumulated experience and sharpened intelligence, and therefore knowledge of many other inventions as well.

• 弓、弦、箭已经是很复杂的工具，发明这些工具需要有长期积累的经验和较发达的智力，因而也要同时熟悉其它许多发明。