单项选择题调教青年公羊时最好用发情盛期或刚刚配过中的母羊做台羊效果更好。 A、正确 B、错误
单项选择题Some of the more common CNC-operated processes include ultrasonic welding, hole-punching and ___________（激光切割）. A、laser cut B、laser cuting C、lasering cutting D、laser cutting
