对于盛装易燃、易爆或毒性程度为中度以上的介质等不允许有微量泄漏的设备，其安全阀密封性能试验不可少于（）次并且每次都应当符合要求。
参考答案：3
Speaker A: Fairly mild for the time of year. Speaker B:().
A. Which season is it now
B. Yes, usually it is very mild at this time of the year.
C. Have you ever had this kind of weather before
D. Yes. Quite different from the forecast.
不论索引是否生效，定位到相同记录上的命令是( )。
A．G0 TOP
B．G0 BOTOOM
C．G0 6
D．SKIP
