Yang Moo-jin, a scholar with the University of North Korean Studies in Seoul, says the North is "playing hard ball".

VOA: standard.2010.05.27

When, you know, studies is like getting really hard because it's like midterm time or final time.

每当期中或期末考试来临，功课很难的时候，

想吃中餐的时候 - SpeakingMax英语口语达人