TWO SIMULTANEOUS CONTINUOUS ACTIONS = WHILE：两个同时进行的连续动作= WHILE
Let me explain, we use while and when when two things are happening at the same time. Now, when we have two continuous actions happening at the same time, then we usually use while.
Right now, I’m recording a video while my husband is working. We have two continuous action, I’m recording and my husband is working. So I’m recording a video while my husband is working.
Or here’s an example in the past, last night, I was watching TV while my father was sleeping. Again, we have two continuous actions. I was watching TV and my father was sleeping. I was watching TV while my father was sleeping. With two continuous actions, we usually use while.
TWO SINGLE ACTIONS AT THE SAME TIME / ONE IMMEDIATELY AFTER ANOTHER = WHEN：在同一时间发生两个动作/一个接一个=WHEN
Now, when we have two single actions that happen at the same time or>You can see that we have two verbs there in the simple past, not continuous.
The phone rang and I picked up. I picked up the phone when it rang. We have two single actions that happened very close together, almost at the same time and so we use when.
Another good example would be when I get home, I take off my shoes. That’s also two single actions. I get home and I take off my shoes. When I get home, I take off my shoes. Or you could say it the other way, I take off my shoes when I get home.
Both while and when are used when two things happen at the same time, but we tend to use while with two continuous actions and when with two single actions.