267.四遍“刚……这时”。be doing...when，be about to do...when，be on the point of doing...when，had just done...when
（1）be doing...when正在干……这时。如：
I was having dinner when a fly fell into my bowl.
我正在吃饭，这时一只苍蝇落到了碗里。
（2）be about to do...when刚准备干……这时。如：
He was about to have a smoke when his father came in.
他刚准备抽根烟，这时他爸爸进来了。
（3）be on the point of doing...when正在干……这时。如：(https://www.daowen.com)
We were on the point of sleeping when someone knocked at the door.
我们正在睡觉，这时有人敲门。
（4）had just done...when刚干完……这时。如：
They had just got home when it began to rain.
他们刚到家，这时开始下雨了。