在行 be expert at sth.; know a job, trade, etc. well 这方面我不在行。 i'm not expert at that. 他对电视机很在行。 he knows a lot about tv set. 她织毛衣很在行。 she is good at knitting a sweater
当场 on the spot; then and there 把这件事当场决定下来 decide the matter on the spot; 当场抓住 catch red-handed; catch in the act ; 当场拒绝他的要求 turn down his request on the spot; 他当场表演了这种新的操作方法。 he gave a demonstration of the new technique then and there.; 当场测试 spot test