tricks of the trade;key to a problem;knack 各行各業(yè)都有～。Each trade has its own tricks./你一旦掌握了～就容易了。It’s easy,once you’ve got the knack./你能否說(shuō)一說(shuō)你賺錢的～？Can you say something about your real knack for making money?/找～ try to find the key to a problem