任何挑战中最难的部分是迈出第一步。
"The scars of history are not always visible, but they are always there."
PID控制器的本质在于它能够根据系统的过去和现在状态预测其未来行为。
The lightning that precedes the thunder is a common image of the warnings that come before calamity.
I'm not a person who gives up on my light.