取一定量的氧化铁与氧化铜的混合物,加入稀硫酸(含0.1molH2SO4),恰好完全反应成盐和水.原混合物中氧元素的质量是( )
— There is somebody under the tree. Is it Mr. Lee?
— It ________ be Mr. Lee. He left for Beijing this morning.