Marine four-stroke diesel engines are mainly ().
A:of crosshead type
B:of trunk piston type
C:of low speed type
D:all the above
出自:海船船员证

完成拼图验证

按住下方滑块,将拼图拖到缺口处后松开。

拼图背景,将小拼图拖到缺口处
向右拖动滑块