past progressive

[bayan said]

Dear sir,
1-would you explain this grammar and illustrate with examples, the grammar says "past progressive isn't used when we're thinking of the action finishing(close).e.g. the police man was smoking on Sunday, the policeman smoked on Sunday" what does the last sentence imply? Does it mean that the speaker watched the policeman till he finished smoking? & why are both simple past & past progressive correct in the first part of the sentence but only the simple past tense is correct in the second part( i.e. with the verb waltzed) I think we ought to use past progressive with waltz,
Because it takes a long time? The sentence is "the room floor shook (or was shaking) while they waltzed".also these sentences:
2- I've read that we say"I was going to auditions every day befor I got my job)but we say"we ate mutton every day"so why is the past progress

[MrPedantic]

Hello Bayan

Usually, the simple past tense presents an action as a whole, while the past progressive presents an action in progress.

Thus:

1. I walked into the room. MrQ was drinking a glass of brandy.

Here, the speaker wants to express the fact that the action (drinking a glass of brandy) was in progress when he entered the room. When we reach the end of the sentence, the action is still not complete: MrQ's glass is still in his hand, and he is still drinking.

2. I walked into the room. MrQ drank a glass of brandy.

Here, the speaker wants to express the fact that the action took place after he walked into the room. When we reach the end of the sentence, the action is complete: MrQ's glass is empty.

Does that make it any clearer? Let me know if not!

Bye for now,

MrP