29. A very beautiful scene spreads in front of the mountain, at the foot of which ______.

A．lies a small village

B．does a small village lie

C．a small village lies

D．is lying a small village

柴油机每作一次功，必须经过进气、（）、燃烧、膨胀和排气五个过程才能实行，进行了这五个过程就完成了一个工作循环。