a mercy he wasn't killed的用法和样例：
- It's a mercy he did not bring us over a black daughter-in-law.
- Benjamin was so excited that it was a mercy he did not awake Tommy Brock, whose snores continued solemnly in Mr. Tod's bed.
- It was a mercy that he died, for he had been racked with pain through his last long illness.
- It is a mercy that you did not go.
- It was a mercy you could not go there.