, English, Math or Chinese

下列各项中加点词的活用类型，与其他三项不同的一项是(　 　)

­—You look so young．Haven’t you graduated from your university? —Yes, I in the English Department of Shandong University for four years

It was three months later _____ hecompleted the job with difficulty.

I have more storybooks than do.— But your books are not as interesting as .