根据短文内容完成下列句子
This summer is very hot, so Alice and her friends are going swimming on vacation. Their teacher Mr
Green gives them suggestions: If you swim in a wrong place, it may not be safe. These years, quite some
people died while they were enjoying themselves in the water, and most of them were students. But some people are still not careful while swimming. They think they swim so well that nothing can happen to them
in water. Summer is here again. If you go swimming in summer, don't forget that better swimmers could
die in water. They died because they were not careful, not because they could not swim. So don't get into water when you are alone. If there is a "No Swimming" sign, don't get into water, either. If you remember these, swimming will be safe.
1. In this summer vacation Alice and her friends are going__ __.
2. Mr Green gives his students ____pieces of advice.
3. From the first suggestion we know that if we swim__ ____,it may not be safe.
4. People should _______while swimming. Many people die not because they could not, but because they are not careful.
5. If there is a" _______"sign, don't get into water.
2NH3（g） ΔH＜0；2SO2（g）+O2（g）
进行中序遍历的结果是________。