Tell me please if I need to use the in the sentences below.
As (the) years pass, white dwarfs cool down and begin to dim.
As (the) years pass, Kate begins to become more reserved.
Actually the first sentence was used with the by a native english speaker, but I do not undestand why it was used. As for the second one I am not sure whether I need to use the or not. Does the phrase as years pass always have to be used with the, If yes, then why?