hard|harder

我觉得数学考试很难。

I think the math test was very ___hard.

她非常努力地尝试了，但她还是不够快。

She tried very ___hard but she wasn't quite fast enough.

我不喜欢在教室里非常努力地工作到很晚。

I don't like to work very ___hard and very late in the classroom.

他更用力地吹。

He blew ___harder.