when it becomes, when it comes to
Noun +
This grammar point is used to indicate a specific time or condition when a natural change occurs, a certain state is reached, or a habitual action takes place. It implies that when a certain point in time or a certain situation arrives, a specific result naturally follows.
This construction connects a noun representing a time, season, or state to a resulting action or condition.
春
When it becomes spring, the flowers bloom.
夜
When it becomes night, it gets cold.
週末
When it comes to the weekend, I go to the library.
二十歳
When he becomes twenty years old, he will drink alcohol.