begin的过去式和过去分词是什么？

We began work on the project in May.

我们于五月份启动了这项工程。

He began by making a few general observations about the report.

开头他先对这个报告作了几点概括性的评论。

Slowly, an image began to appear on the screen.

屏幕上慢慢地出现了一幅图像。

He took one smell of the liquid and his eyes began to water.

他闻了一下那种液体，就流起泪来了。

The music and wine began to make him feel sexy.

那音乐和酒逐渐使他性欲萌动。