《汉书·传·杜周传》
延年愚钝，认为丞相居位已久，又曾在先帝时任职，非有大变故，不可抛弃。
延年愚，以为丞相久故，及先帝用事，非有大故，不可弃也。
“In my humble opinion, the Chancellor has held his position for a long time, and he also served the previous emperor. He cannot be dismissed without a major incident.”