题目

如图所示，轻弹簧一端固定在墙上，另一端连一挡板，挡板的质量为m，一物体沿光滑水平面以一定的速度撞向挡板，物体质量为M，物体与挡板相接触的一面都装有尼龙搭扣，使得它们相撞后立即粘连在一起，若碰撞时间极短（即极短时间内完成粘连过程），则对物体M、挡板m和弹簧组成的系统，下面说法中正确的是（   ） A．在M与m相撞的过程中，系统的动量守恒而机械能不守恒 B．从M与m粘连后到弹簧被压缩到最短的过程中，系统的动量不守恒而机Since 1989, Dave Thomas, who died at age 69, was one of the most recognizable faces on TV． He appeared in more than 800 commercials （商业广告） for the hamburger chain named for his daughter． “As long as it works,” he said in 1991, “I’ll continue to do those commercials．” Even though he was successful, Thomas remained troubled by his childhood． “He still won’t let anyone see his feet, which are out of shape because he never had proper-fitting shoes,” Wendy said in 1993． Born to a single mother, he was adopted as a baby by Rex and Auleva Thomas of Kalamazoo in Michigan． After Auleva died when he was 5, Thomas spent years on the road as Rex traveled around seeking construction work． “He fed me,” Thomas said, “and if I got out of line, he’d beat me．” Moving out on his own at 15, Thomas worked, first as a waiter, in many restaurants． But he had something much better in mind． “I thought if I owned a restaurant,” he said, “I could eat for free．” A 1956 meeting with Harland Sanders led Thomas to a career as the manager of a Kentucky Fried Chicken restaurant that made him a millionaire in 1968． In 1969, after breaking with Sanders, Thomas started the first Wendy’s Old Fashioned Hamburgers, in Columbus, Ohio, which set itself apart by serving made-to-order burgers． With 6,000 restaurants worldwide, the chain now makes $ 6 billion a year in sales． Although troubled by his own experience with adoption, Thomas, married since 1954 to Lorraine, 66, and with four grown kids besides Wendy, felt it could offer a future for other children． He started the Dave Thomas Foundation （基金会） for Adoption in 1992． In 1993, Thomas, who had left school at 15, graduated from Coconut Creek High School in Florida． He even took Lorraine to the graduation dance party． The kids voted him Most Likely to Succeed． “The Dave you saw on TV was the real Dave,” says friend Pat Williams． “He wasn’t a great actor or a great speaker． He was just Joe Everybody．” 59． What is the article mainly about? 　　　 A． The life of Dave Thomas．　　　 　　　　 B． The dream of Dave Thomas． 　　　 C． The schooling of Dave Thomas．　 　　　　 D． The growth of Dave Thomas’s business． 60． What do we know about his childhood? 　　　 A． He lived a poor life．　　　　　 　　　　　 B． He had caring parents． 　　　 C． He stayed in one place．　　　　 　　　　 D． He didn’t go to school． 61． Choose the right time order of the following events in Thomas’s life． 　　　 a． graduated from high school 　　　 b． started his own business 　　　 c． became a millionaire 　　　 d． started a foundation 　　　 e． met Harland Sanders 　　　 A． e, b, c, d, a B． a, e, c, b, d C． e, c, b, d, a D． a, e, b, c, d 62． “He was just Joe Everybody．” （in the last paragraph） means ______． 　　　 A． Dave was famous B． Dave was ordinary 　　　　　　　　　　　 C． Dave was showy 　　　 D． Dave was shy