stuffy的比较级是什么

　　例句：

　　Museums have been trying hard to shed their stuffy image.

　　博物馆一直努力改变自己沉闷的形象。

　　It was hot and stuffy in the classroom.

　　教室里很闷热。

　　That stuffy professor gives very boring lectures.

　　那个古板的教授讲课无聊透顶。