at the idea of,at the mention of,at the touth of

at the idea of,at the mention of,at the touth of
at the idea of,at the mention of,at the touth of,at the sound of
关于这种用法 里面的mention,sound这些词的名词还是动词呢?at the（动词还是名词） of
还有at the idea of和at the thought of 这2个有什么区别