It was Sunday. We decided to go for a picnic.
合并为包括独立主格的句子为:
It being Sunday, we decided to go for a picnic.
能不能改为如此的:
It was Sunday, we deciding to go for a picnic.
We deciding to go for a picnic, it was Sunday.
看得出,这位网友的思维非常活跃。在两个含有不同主语的简单句中,把其中一个转化为“独立主格结构”。
【请注意】形式服从于内容,句子的结构形式,是为表达语义内容服务的。假如只考虑外在形式的多样化,而忽视了语言的表意功能,那就是本末倒置了。
你给的两个句子,之间存在着因果关系,句子的信息重心在第二个句子上面。所以,只能把前句变成非谓语形式,表示缘由:
It was Sunday. We decided to go for a picnic. 变为:
It being Sunday, we decided to go for a picnic.
所以,后面的两个转换毫无意义,事实上就是不对的。