A:H2O
B:NaOH溶液
C:盐酸
D:石蕊试液
(3+2)×20 (32+56)×9 (57+23)×12
3×20+2×20 32×9+56×9 57×12+23×12
鉴别空气、氧气和二氧化碳三瓶气体,最佳的做法是( )
—I live near school. I go to school ________