sit for有以下两种用法
1．take an examination应（考）；参加（考试）
His teachers said he should sit for university．他老师都说,他应该参加高考.
2．be a member of parliament for a certain place代表…在议会占一个席位
文中He sits for the city of Birmingham．他是伯明翰市选区选出的议员.