It will be something more like "let's study in earnest everyday".
好好学习
天天上
Those will probably be the offending clauses or whatever you want to call them. The reduplication of "good" and "day" produces different words.
Even the girl doesn't know what he's talking about, apparently. 说啥呢 basically means that, but in dialect. I'd be interested to know where the book came from. Taiwan, maybe?
Edit: this is a phrase, apparently:
好好学习, 天天向上
"study hard, improve everyday"