编号

例句：

1. 1. The computer has a serial number on the back.
   这台电脑背面有个序列号。
2. 2. We need to keep track of our numbers in order to win the lottery.
   我们需要记下我们的号码才能赢得彩票。
3. 3. The police are using a new system to identify and catalogue all the missing numbers.
   警方正在使用一个新的系统来识别和登记所有失踪的号码。