Mr. King works very long hours every day. He usually gets up at 5:30. He brushes his teeth quickly and goes to his workplace (工作地点). Then he runs with some kids. After that he takes a shower.
向三份0.1mol·L-1 CH3COONa溶液中分别加入少量NH4NO3、Na2SO3、FeCl2固体（忽略 溶液体积变化），则CH3COO- 浓度的变化依次为 A．减小、增大、减小 B
Scientists are convinced ___________ the positive effect of laughter ___________ physical and mental health. A. of; at B. by; in C. of; on D. on; at
Frank Woolworth was born in Rodman, New York, in 1852. His family were very poor farmers, and there was never enough to eat. Frank decided he did not want to be a farmer. He took a short business cou
下列物质中铁的质量分数最小的是 A.FeO B. Fe3O4 C.FeS D.Fe2O3
光在真空中传播速度为_____m/s;为实现我国的探月计划，向月球发射的激光到达月球并返回地面共需2．56s、则地球和月球间的距离是______m。
把镁粉中混入的少量铝粉除去，应选用的试剂是( )A．稀盐酸 B．新制的氯水 C．烧碱溶液 D．纯碱溶液
思想解放是社会变革的先导，巴黎公社、俄国十月革命、新中国的成立等对世界发展产生重要影响的社会实践，所依据的理论来自：（ ）A．《共&#
