1、这一章是关于热能转化成动力的。

This chapter is about the transformation from heat to dynamic energy.

2、一群人自发地聚集在事故现场。

A crowd of people assembled spontaneously on the spot of the accident.

3、这次争吵是由误会引起的。

The quarrel originated from misunderstanding.

4、1949年后，军队接管了这个城市。

The Army took over the city after 1949.

5、为了你的健康，你不该承担太繁重的工作。

For the sake of you health，you shouldn't take on too heavy work.