25℃和101kPa时,乙烷、乙炔和丙烯组成的混合烃32mL,与过量氧气混合并完全燃烧,除去水蒸气,恢复到原来的温度和压强,气体总体积缩小了72mL,原混合烃中乙炔的体积分数为
- Where did you buy that? - Dad _______ it in Chinatown.
- Happy New Year! - ________________.
We know Hainan is in the ________ of China.
There is a teacher’s table _______ our classroom, and two trees ______ our classroom, too.
Let’s _______ there, because it is very ______.