单项选择题赫兹伯格在提出“双因素”理论之前,曾对美国匹兹堡地区二百名工程师、会计师做了调查访问,他发现使员工感到满意的因素包括( )方面。
单项选择题When the crude oil is obtained from the field, it is taken to __________ to be treated. The commonest form of treatment is heating.