He usually gets up at 6 o'clock in the morning ,but he had t

He usually gets up at 6 o'clock in the morning ,but he had to get up very early yesterday morning..
He usually gets up at 6 o'clock in the morning ,but he had to get up very early yesterday morning because he wanted to catch a train.
这里的get为什么不用过去式got?
catch为什么不用过去式?
because he wanted to catch a train.
这里的catch为什么不用过去式？