英语语法分析

At last a calculational example and some valuable conclusion were given.

最后给出了算例，并得出了一些有价值的结论。

Several system reliability models and their calculational methods are introduced.

介绍了几种系统可靠性模型及其相应的可靠性计算方法。

Then, give the economic significance and calculational methods of these four kinds calculational methods.

然后，重点介绍了四种类型的技术进步贡献的经济意义及计算方法。