begin的過去式和過去分詞形式

例句：

The pressure of work is beginning to get to him.

工作的壓力使他煩惱起來。

We began work on the project in May.

我們於五月份啓動了這項工程。

Work has begun on the construction of the new airport.

新機場的'修建已經開工。

Could you go back to the beginning of the story?

你能不能回到故事的開頭？