Do you enjoy ______ the piano? [ ]

A. play

B. playing

C. played

D. plays

涡流室式燃烧室混合气的形成特点，是依靠定向而强烈的（）进行混合和燃烧。

A.燃烧涡流

B.压缩涡流

C.进气涡流

D.压缩紊流巧