"老人凡事都相信，中年人凡事都怀疑，年轻人凡事都知道。"

Simplified Meaning:

As people age, their way of thinking changes. Older people often trust what they hear because they have seen so much in life and may become more accepting. Middle-aged people tend to question things more; they are cautious and skeptical because they have experienced enough to know not everything is as it seems. Younger people, full of energy and confidence, often feel like they have all the answers and understand everything better than others. For example, if there's a new social media app, young people might quickly embrace it, thinking they know how it works and how to use it best. Middle-aged folks might be more hesitant, wondering if it's safe or worth their time. Older people might just go along with what they hear about it from others. This idea suggests different stages of life bring different perspectives on how much we trust, doubt, or feel certain about things. Knowing this, we can become more aware of how our thinking and attitudes change with age and try to balance trust, doubt, and confidence in a healthy way.