用法:
1 (Brit) (of films) parental guidance, ie containing scenes unsuitable for young children （指电影）须有家长指导观看的（有儿童不宜的镜头）.

用法:
2 paying guest. 搭伙房客.

用法:
3 postgraduate （大学的）研究生.

• on earth(on the earth)
• on fire(on the fire)
• on guard(on one's guard)
• on hand(on all hands)
• on hand(on one's hands)
• on occasion(on one occasion)
• on one's account(on one's own account)
• on one's life(in one's time)
• on one's part(on one's side)
• on order(on orders)
• on pain of(under pain of)
• on schedule(on the schedule)
• on stage(on the stage)
• on the board(on the boards)
• on the contrary(in contrast)
• on the contrary(on the other hand)
• on the contrary(to the contrary)
• on the pretence of(under the pretence of, on/under the pretext of)
• on the quick(to the quick)
• on the side(on the …side)
• on the table(upon the table)
• on the turn(to a turn)
• on the watch against(on the watch for)
• on the water(on the waters)
• on the water(under water)