这些古旧的门钉曾是用来装饰城堡大门的。

These antique ___doornails were used to decorate the castle's gate.

那条鱼在阳光下暴晒了一整天，现在像门钉一样死透了。

The fish had been under the sun all day and now it's as dead as a ___doornail.