回油孔式高压油泵的穴蚀主要发生在()上。
A.柱塞外圆面
B.套筒内孔
C.圆柱配合面
D.螺旋槽
参考答案:D
Luckily, we’d brought a road map, _________ we would have lost our way.
A.without it
B.with that
C.without which
D.without that
()是社会主义道德建设的基础。
A、社会公德
B、职业道德
C、家庭美德