半终粉磨系统
粤菜主要覆盖在() ["长江中游地区","长江下游地区","珠江流域","黄河流域"]
万用表电压或电流量程的意义是()。 ["A、量程乘以指针的指示值;","B、量程除以指针的指示值","C、指针满刻度时的值;","D、指针为零时的值"]
某万用表有500V、250V、50V等电压量程,若测量270伏左右的电压,应选用()量程。 ["A、500V","B、250V","C、270V","D、500V或250V"]
相传,豆腐的发明者是西汉的() ["刘荣","刘彻","刘秀","刘安"]
空气分级