youdao

这是一种三位数字的代码，印在信用卡的背面，多数，但不是所有的电子零售商在进行买卖交易是都要求提供这一代码。

That's the three-digit code on the back of every credit card that most, but not all, e-retailers ask for when making a purchase.

youdao

不同的技术可帮助实现此直接印刻的工艺，如激光/化学雕刻、点式打标和喷码打印技术。

Different technologies are available to directly mark objects: laser / chemical etching, dot peening and ink jet printing.

youdao