Simone
1. 从句意来看,用because he thought differently也是可以的.
但是,此时because引导的是一个原因状语从句,整个句子结构就变成了主从复合句,而不是并列句了.
所以,此种改法是不符合题目要求的.
另：此句还可以用so来引导并列句,即：
He thought differently, so he shook his head.
2. 该句要变成复合句的话,可以用楼主自己写的句式：
He shook his head because he thought differently.（句中的逗号可要可不要）
或：Because he thought differently,he shook his head. 原创回答团（第159号团员）
