求英语作文 名言怎么引用？ 不要复制别人的！！！

as is quoted by Sb ++".............''
as an old saying goes,"......''
as has been stated by Sb,".....''
Sb,。。。（职业或介绍），once said,,"......''

as the old saying goes,
逗号后加你想用的名言喽。

就说某某人once said that：“。。”。GRE作文范文里就有这么用的