are的过去式是什么

　　With the coming of modern technology, many jobs were lost.

　　随着现代技术的到来，许多工作岗位不复存在。

　　All the statistical computations were performed by the new software system.

　　所有的统计计算均由新的软件系统完成。

　　A number of measures were taken to alleviate the problem.

　　采取了一系列措施缓解这个问题。