Hi,

What is the difference among them? Which one(s) would you use?

A. BEFORE

1- I brushed my teeth before I had gone to bed. No reason to use PP. Just use simple past

2- I brushed my teeth before I went to bed. Yes

3- I had brushed my teeth before I went to bed. No reason to use PP, because sequence of events is clear withiout it. Just use simple past

B. AFTER

1- I went to bed after I had brushed my teeth. No reason to use PP. Just use simple past

2- I went to bed after I brushed my teeth. Yes

3- I had gone to bed after I brushed my teeth. No reason to use PP, because sequence of events is clear withiout it. Just use simple past

additional questions:

a) Is it possible to use "past perfect" both in the main clause and in the subordinate clause (at the same time) in the sentences above? ie 'I had brushed my teeth before I had gone to bed'. I suppose it's possible, but you really need a context where you want to stress that you did these things before some other event. eg

I accidentally went into the wrong bedroom and got into bed with our guest, my wife's beautiful friend from university. Fortunately, I had brushed my teeth before I had gone to bed, so she didn't tell me to get out of bed. Even here, I'd actually prefer simple past in before I went  to bed.

b) Is it possible to use "past continuous"  either in the main clause or in the subordinate clause with "after" or "before"? 

I was brushing my teeth before I went to bed. I guess you could say this. It stresses the duration of the brushing activity. It also focuses on the time of brushing, eg

I was brushing my teeth before I went to bed when suddenly there was an earthquake.

I brushed my teeth before I was going to bed. This sounds strange.

Best wishes, Clive

Clive wrote:

<3- I had brushed my teeth before I went to bed. No reason to use PP, because sequence of events is clear withiout it. Just use simple past > Best wishes, Clive

How about here?

 I had brushed my teeth before I went to bed, but now they felt all furry again.

Hi guys,

 I had brushed my teeth before I went to bed, but now they felt all furry again. You can certainly say this. The PP is not necessary, as 'before' makes the timing obvious, but using PP adds emphasis to the timing. It's the speaker's choice in such a case.

I also very much agree with Goldmund's comment that It is further my opinion that it is the greater perspective of the paragraph that we must consider in the choice of the past perfect.

In Goldmund's two examples, particularly the second one, the PP is needed to make the timing clear.

Best wishes, Clive