【单选题】This is the most boring speaking I have ever heard.
【单选题】边际报酬递减规律适用的条件是
C.
其他生产要素投入量不变,只有一种生产要素投入改变
【判断题】开机和关机时,一定要严格遵守机床的开机 和关机顺序。
【单选题】---- Hello. ______? ---- Speaking. A.Who’s that speaking B. Are you John speaking C. May I speak to David, please D. Who are you speaking