begin的过去式和过去分词形式

例句：

The pressure of work is beginning to get to him.

工作的压力使他烦恼起来。

We began work on the project in May.

我们于五月份启动了这项工程。

Work has begun on the construction of the new airport.

新机场的'修建已经开工。

Could you go back to the beginning of the story?

你能不能回到故事的开头？