某混合气体通过溴水(使其褪色),再通过灼热的氧化铜(使其黑色变红色),再通过无水CuSO4白色粉末(使其变蓝色),再通过澄清石灰水(石灰水由清变浑再变清),最后剩余气体在空气中点燃,火焰呈淡蓝色,这种混合气体是( ) A.水煤气 B.高炉煤气 C.石油液化气 D.焦炉煤气 I’m surprised to see you drink so much. You ________. A. used B. didn’t use to C. were used to D. weren’t use d to