一些短语，包括名词性短语或分词短语可以作说明性状语，用来描述句子的背景情况。可以转换成一个并列句。

1. Founded in 1900, the university has a history of more than 100 years. =

The university was founded in 1900, so it has a history of more than 100 years.

2. About four metres long, the room served as a small reception hall for important visitors. =

The room was about four metres long, and (it) served as a small reception hall for important visitors.