题目

I clearly remember the day when my little brother was born: January 1, 1994. One of my favorite family photos shows me lying with my mother in the hospital bed, happy but un- aware of the small, sleeping baby in the background. I stayed with my grandparents for the weekend of my brother’s birth, excited about my new brother but not yet aware of what having a little brother would mean. I didn’t truly realize what was going on until we were in the hospital room at Duke University----coincidentally (碰巧地), the same room in which I had been born two years earlier. When I looked at在四川抗震救灾中，一架号称“空中巨无霸”的米?26重型运输直升机，通过钢缆和机身相连，一次将一台13.2吨的挖掘机，空运到唐家山堰塞湖坝顶参加抢险．当直升机吊着挖掘机（如图所示），水平匀速飞行50米，钢索对挖掘机做的功为    J．到达目的地下降过程中，坐在直升飞机里的人看见地面在迅速上升，他选择的参照物是    ．