阅读理解。阅读下列短文, 从给的四个选项 (a、b、c和d) 中, 选出最佳选项。
when was the last time someone did something unexpectedly nice for you？not someone you knew，but a total stranger？it's happened to me a few times，but two instances really stand out.
a few years ago，i was dining out with a person who kept going on and on about himself，completely oblivious to the fact that i wa
