人类使用的能量绝大部分是从______中获得的内能．在燃料燃烧的过程中，燃料的______能转化为______能．现代的机动车是靠热机把______能转化为______能．

Peter _____ a little money every month so that he can buy a car of his own in the near future.[ ]

A. sets aside

B. sets about

C. sets off

D. sets out