A:不变,降低,降低
B:降低,不变,增大
C:不变,增加,增大
D:降低,增加,增大
天然气的主要成分是甲烷,常作燃料.甲烷完全燃烧的化学方程式可表示为:CH4+2O2CO2+2H2O.
A:____that?
B: It's a radio.
A:____often listen to the radio?
B:____, I do.
A:____do you often listen to?
B: I often listen to music.
A:____do you often listen to the music?
B: In the park or at home.