Th bll rang and th class was ovr. Th classroom bcam noisy. Som studnts wnt out of th classroom. I was just chatting with som of my classmats whn Li Hong cam to m. Sh smild and said to m, Whats four minus four? Do you know? Its zro. That is asy. answrd I. But Li Hong shook hr had and said Its wrong. Its ight. Why? Thats impossibl! You will undrstand if you cut down four cornrs of a dsk. said Li Hong. Is that a jok? Oh, ys. W all laughd. During th class brak, w had a good rst. W oftn hav a plasant brak.