— David, why are you so excited?

—My father has made a _________ that he will take me to Tibet next month.

A．face

B．contribution

C．promise

D．mistake

燃烧0.1 mol两种气态烃的混合物，生成3.58 L CO₂（标准状况）和3.6g H₂O，则混合气体中 [ ]

A．一定有甲烷    

B．一定有乙烷   

C．一定无甲烷    

D．一定有丙烷