依次填入下面一段文字横线处的语句，衔接最恰当的一组是（　）
中国古典美学讲和谐。__________，可高度概括为阴阳统一，刚柔统一。__________，而强调你中有我、我中有你的统一。__________，所以又称之为“中和”，__________。__________，孔子观东流之水，喟然长叹“逝者如斯夫，不舍昼夜”。
①这种和谐由于做到恰到好处
②“中”，恰当之谓也
③和谐不是同一重复，而是众多因素对立的统一
④中华民族十分重视天人合一之美
⑤这种统一不强调部分与部分或部分与整体之间的统一

如图所示电路中，已知R₁>R₂，电源电压U保持不变，在相同的时间内四个电路中总共放出的热量由多到少的顺序是

人体有多种方法保护自身免受病患。下列自身保护方法中，不属于人体免疫功能的是（        ）

You can ride your bike to school, but remember to be careful ____ .　　

This magazine isn't popular with the students though it____  every week.

It's difficult____  both the old and the young about the program at the same time.

The kids clapped and shouted ____ when the actor appeared.

Though he is very busy, he goes to the movies to relax____ 

The children are interested in playing the piano, so they need more____ 

The visitors ____  not to swim in this river for several times.

There are no students in the classroom. They ____  on the playground.

Thank you for____  the museum. We've learned a lot.

You must do more exercise, ____  twice a week.