如图，物块A放在直角三角形斜面体B上面，B放在弹簧上面并紧挨着竖直墙壁，初始时A、B静止；现用力F沿斜面向上推A，但AB并未运动。下列说法正确的
某人造地球卫星质量为m，其绕地球运动的轨迹为椭圆，它在近地点时距地面高度为h1，速度为V1，加速度为a1；在远地点时，距地面的高度为h2，速度为V2
（2008海南）亚里斯多德曾将城邦的政治机构划分为三部分：“其一为有关城邦一般公务的议事机能；其二为行政机能部分┅┅其三为审判机能。”在这
用化学的观点解释下列成语，错误的是（ ） A．花香四溢：分子在不断运动 B．釜底抽薪：将可燃物撤出燃烧区 C．点石成金：将石头变成黄金 D．粉
—I was wondering whether you could remember that name. —Oh, I’m afraid that ______ me for the moment. A. reminds B. puzzles
已知：①C(s)+O2(g)CO(g) ΔH1=-110.35 kJ·mol-1②CO(g)+O2(g) CO2(g) ΔH2=-282.57 kJ·mol-1③C(s)+O2(g)CO2(g) ΔH3，则ΔH3等于( )A.+172.22 kJ·mol-1
He is English boy. We all like him. A. a B. an C. the
He wishes the holiday season would end already. His back aches, his red suit feels like a spacesuit, his cheeks have gone tight from smiling for 12 hours — and still the kids keep coming and coming,
的相反数为 ，绝对值为 .
