99色精品-9色在线-99色在线-99色视频 国产欧美日产一区二区三区_亚洲精品亚洲人成在线观看_四虎在线精品永久观看_免费一级a一片久久精

單項選擇題

The four-stroke cycle is so called because it takes () to complete the processes needed to convert the energy in the fuel into work.

A.two strokes of the piston
B.four strokes of the piston
C.one revolution of the crankshaft
D.four revolutions of the crankshaft

微信掃碼免費(fèi)搜題