Thx! Some of these could be explained by understanding

来源: 于 2010-08-05 16:07:42 [博客] [旧帖] [给我悄悄话] 本文已被阅读：次

the use of single letter.
By this way, I remember some usage easily, such as ashamed for vs ashamed of, historical vs historic. I assume that no one has ever analyzed in my way.