Yang Heng is a very careful person. Even when crossing the zebra crossing, he has to observe it eight times after the green light is on. He will not pass until he confirms that there are no vehicles running the red light or vehicles turning quickly on both sides. But he was so careful, but something happened in one winter! Duo duo, duo duo, ah, it’s so cold, so cold, let me light up the stove and have a good sleep... Oh, no, I forgot to close the window Open up a little gap, this, this, why can't I move...Yang Heng found that he was poisoned by some gas...