题目

Most people think sleepwalkers (梦游者) walking around at night. But in fact, not all sleepwalkers walk. Some only sit up or get out of bed or act like how they often do during the day when they are sleeping! But most sleep walkers do get up and go around for a few seconds or half an hour.Sleepwalkers' eyes are open, but they don't see the same way as they do during the day, and they often think they are in different rooms of the house or different places. Sleepwalkers usually go back to bed themselves and they don't remember it in the morning.Scientists say that sleepwalking may sometimes 11．下列现象中质量会发生改变的是（　　）A．冰熔化成水B．宇航员把衣服由地球带到月球C．把橡皮泥由圆形捏成方形D．用砂轮打磨过的刀