1、非谓语动词,准确的说是过去分词短语作后置定语可以转化为一个含有被动语态的定语从句；现在分词（表示主动）或不定式（一般表示主动,只有在 to be done 是才表示被动）作定语情况就不同了.这里是过去分词,因此下面你改写的句子是正确的：
A local school teacher,who was called Zhou Yu,heard strange noises outside his window every night.
2、时态不同,动词表达的行为或状态时间也就不同,如果不考虑上下文的语言情境,下面的句子虽然意思有别,但都符合语法——
* who was called 意思是这个人“说话以前被称为”
* who is called 意思是这个人“说话时被称为”
但是如果放在具体的文句中,就得是说话时所指的具体时空而定,如：
* A local school teacher,who was called Zhou Yu,heard strange noises outside his window every night.
这是由于主句 A local school teacher heard …中,其行为出现在过去的一段时间 every night,因此只能用 who was called；如果改用 who is called,就出现了时空错位.
* A local school teacher,who is called Zhou Yu,hears strange noises outside his window every night.
由于主句 A local school teacher hears …中,其行为在说话时经常发生（every night）,因此只能用 who is called.如果改用 who was called,只能理解为“他曾经称为周瑜”,言外之意就是现在可能已经改名了.
3、定语从句前加逗号与否,需要确定该定语从句是限定先行词的概念范围,还是对先行词进行补充说明.
* 没有逗号叫做限制性定语从句,也就是说从句限定了先行词的范围,因此 a teacher who is called Zhou Yu heard… 意思是“一个叫周瑜的（而不叫做其他名字的）老师听到过……”.
* 有逗号叫做非限制性定语从句,它的作用是对先行词进行进一步说明.因此a teacher,who was called Zhou Yu,heard … 意思是“一位老师听到过……,他叫周瑜”,或者“有个老师叫周瑜,他听到过……”.