You don't want to say: " you're a fuddy duddy" .

“老顽固。”

Mr Smith he's such an old fuddy duddy I can't stand any of his history classes.

史密斯先生老顽固，我无法忍受上他的历史课。

If indeed I still sound like a lecturer, and somewhat of an old fuddy- duddy, it is because old rock head Ruburt continues in his own ways, as is to be expected.

如果说我听起来确实还像，有点像老古板，那因为老顽石鲁伯还在继续我行我素，这意料中的。