How did crossbows evolve from bows?

When using bow and arrow, you need to hold the bow and arrow in one hand and pull the string in the other, which affects the accuracy of archery. In order to overcome these shortcomings, the ancient people in China drew lessons from the original bow clip used to kill prey, and came up with the original idea of making crossbows, that is, installing a directional device and a mechanical launching system on the bow arm, which greatly improved the hit rate and launching power, and a crossbow with better performance than the bow was born. From this point of view, crossbows are bows with arms. As a conventional weapon in ancient China, it obviously evolved from the bow.