I used to quarrel a lot with my parents, but now we _____ fine. [ ]

A. look out

B. stay up

C. carry on

D. get along

200℃时，11．6g CO₂和H₂O的混合物气体与足量的Na₂O₂反应，反应后固体增加了3．6 g，则原混合物的平均式量为[ ]

A．5．8

B．11．6

C．23．2

D．46．4