spare fuse

例句：

1. 1. The car's engine has a spare fuse to prevent the car from breaking down in the middle of the road.
   这辆车的引擎有一个备用保险丝，以防在路上抛锚。
2. 2. The engineer replaced the spare fuse on the circuit board.
   工程师更换了电路板上的备用保险丝。
3. 3.The mechanic checked the spare fuse and found it to be working properly.
   机械师检查了备用保险丝，发现它工作正常。