key letter in context

例句：

1. 1. The key to solving the problem lies in finding the right solution.
   解决问题的关键在于找到正确的解决方案。
2. 2. He had a key to the door, so he could let himself in.
   他有门的钥匙，所以他可以自己进来。
3. 3. She gave me the key to her car, so I could drive it home.
   她给了我车钥匙，所以我能开车回家。