The lyrics of a sigh on earth express what emotion it

The world a sigh generally refers to all things in the world are not of their own volition, and there is no way to control, in the end can only be replaced by a sigh of human beings. Generally used to describe the world is unpredictable, there is no way to artificially control, for the things of the world can only use a lifetime long sigh to express the inner confusion and ignorance. Generally expresses the state of mind and emotions that all things cannot be controlled.