在行 be expert at sth.; know a job, trade, etc. well 這方面我不在行。 i'm not expert at that. 他對電視機很在行。 he knows a lot about tv set. 她織毛衣很在行。 she is good at knitting a sweater
當場 on the spot; then and there 把這件事當場決定下來 decide the matter on the spot; 當場抓住 catch red-handed; catch in the act ; 當場拒絕他的要求 turn down his request on the spot; 他當場表演了這種新的操作方法。 he gave a demonstration of the new technique then and there.; 當場測試 spot test