【题目】 —Michael was late for Mr. Smith's chemistry class this morning.
—________? As far as I know, he never came late to class.
A.So what
B.Why not
C.Who cares
D.How come

【答案】D
【解析】句意：——今天上午迈克尔上史密斯先生的化学课迟到了。——怎么回事？就我所知，他上课从不迟到。so what那又怎样；why not为什么不；who cares谁在乎呢；how come怎么回事。故选D。