This is the 641st most frequent Chinese word.
在于
"To lie in," "to depend on," or "to consist in."
Used to indicate the essence or basis of something.
成功在于坚持。
Success lies in persistence.
Emphasizes the focus or central aspect of a matter.
问题的关键在于如何解决。
The key to the issue lies in how to solve it.
Describing the source or reason for an experience or feeling.