6. You must stay away from this deep river because it is very dangerous to swim in it.

6. 你必须远离这条深河，因为在里面游泳很危险。

7. The modern world is still influenced by Confucius's ideas.

7. 现代世界仍然受到孔子思想的影响。

8. The best way to keep healthy is to exercise more.

8. 保持健康的最好方法是多运动。

And I think running is a good choice.

我认为跑步是个不错的选择。