In exchange, he guarantees an above-market price for each animal and a calf-to-customer electronic ear tag ID system like that used in the European Union.
2019年12月六级真题（第三套）阅读 Section B
柯林斯高阶英汉双解学习词典释义
N-VAR
身份证明;身份证件
If you have ID or an ID, you are carrying a document such as an identity card or driver's licence which proves that you are a particular person.