第4题: [单项选择]Crew chiefs supervised engines, switches and lights that told them how each item of equipment was functioning. A. observed B. preserved C. monitored D. nurtured 参考答案:C 答案解析:[解析] 本题中,supervised的意思是“监督,管理,指导”。四个选项中,monitored的意思是“监控”,如:a television wave form monitor(电视波形监视器)。