double-lock

例句：

1. 1. The safe was double-locked, so it couldn't be opened without a key.
   这个保险箱是双重锁的，没有钥匙是无法打开的。
2. 2. She double-locked the door before leaving for work.
   她离开前把门双重锁上了。
3. 3. The security guard double-locked the gates to prevent intruders.
   保安员双重锁住了大门以防入侵者。