番号

例句：

1. 1. The computer has a serial number on the back.
   电脑背面有一串序列号。
2. 2. She entered her serial number when checking in.
   她输入了入住时的序列号。
3. 3. The police used the serial number to track down the thief.
   警方利用序列号追踪到了小偷。