题目

根据括号中所给的汉语写出单词，使句子意思完整正确。 1. Bill is too fat. He plans to eat less        (肉) to keep fit. 2. We need a confident        (领导者) to help us deal with these difficulties.  3. We        (举行) a charity show and raised some money for poor families yesterday. 4. Our English teacher enjoys travelling. She        (很少) stays at home during holidays. 5. Wild animals aren’t        (自由的) because they may become dishes on the table any time.物块A质量为m，置于光滑水平地面上，其上表面固定一根轻弹簧，弹簧原长为L0，劲度系数为k，如图所示．现将弹簧上端B缓慢的竖直向上提起一段距离L，使物块A离开地面，若以地面为势能零点，则这时物块A具有的重力势能为（　　）A．mg（L+L0）B．mg（L+L0+mgk)C．mg（L-L0+mgk)D．mg（L-mgk)