将句子翻译成英语:作为班长,马克认为处理好班级事务是自己的责任.（it作形式宾语）

As a monitor, Mark think that handle classes affairs are his own responsibility.

As the monitor,Mark thinks it's the responsibility to deal with the class affairs.

Being the monitor of the class ,Mark thinks it his duty to settle his classmates' affair.
结构：主语+think + it( 形式宾语）+名词、形容词+不定式（真正的宾语）