He says dinosaurs probably could not get off the ground to fly.

VOA: special.2010.03.16

And he convinced me that they actually could fly.

然后他说服我说，企鹅其实是能飞的。

I used to实战 - SpeakingMax英语口语达人

But he could not fly as often as he liked.

VOA: special.2009.03.18