""人们自己创造自己的历史，但他们不是随心所欲地创造历史。他们不是在自己选择的环境中创造，而是在已经存在的、从过去传承下来的环境中创造。""

Simplified Meaning:

People shape their own future and the events in their lives, but they can't do it exactly how they want. They have to work with the situations and conditions that already exist, which come from the past. Imagine a soccer player joining a game halfway through; they can try to score goals and play their best, but they can't change the rules of the game or the score that existed before they joined. In the same way, when people try to change their lives or achieve something, they have to deal with challenges and situations left by earlier generations. This means understanding history and other people's experiences helps us make better decisions. For instance, if you want to start a new business, you need to consider existing market conditions, past business trends, and economic factors. By being aware of these circumstances, you can plan better and increase your chance of success.