括号里是过去分词短语作后置定语，可以改为关系分句。章振邦书中称一个先行项后带的两个关系分句为“双重关系分句”。双重关系分句分两种情况（见下文）。

网友的的句子改为关系分句：

There is a long novel which is called the Da Vinci Code which was written by an American writer Dan brown.

其中，第一个关系分句 which is called the Da Vinci Code 修饰 a long novel，第二个关系分句 which was written by an American writer Dan brown 修饰 a long novel which is called the Da Vinci Code。要注意第二个关系分句的先行项不是 a long novel，而是它与第一个关系分句整体作先行项。这种情况下，两个关系分句处于不同层次。

另一种情况是两个关系分句由并列连词连接，处于同一层次：

You’ll easily find us; just look for a house whose windows need washing and whose fence needs repairing.