Let's first talk about the following two sentences:
1- Sara went to bed as soon as she had finished homework.
2- Sara went to bed as soon as she finished homework.
I think your confusion is valid because we use the past perfect when we talk about something that took place before another thing in the past. So the use of the past perfect comes across in the first sentence but the use of the past simple in the second sentence doesn't. Am I right? In fact, we don't need to use the past perfect unless it is necessary or unavoidable to do so. Even if we talk about one action happening before the other one, it is possible to use the simple past for both actions if we think it is not necessary to highlight or emphasize the happening of the earlier action. It sounds natural to avoid using the past perfect where the simple past works, which is used to refer to something or several things happening in sequence (one after another) in the past.
So both of the sentences are grammatically correct. However, I'll prefer the second phrase to the first one.
As for the last two sentences, it is correct to say that "everyone had gone home when Sara got to the party", but it's not grammatically correct to say that "everyone had gone home when Sara had got to the party". It doesn't make sense. In the past perfect when we talk about two events, we use the simple past in one clause and the past perfect in the second clause.
Let's now talk about the following sentence you are confused about:
"Everyone went home when Sara had got to the party".
There is nothing wrong with this sentence, but the meaning is other way round. It means that first Sara got to the party and then every one went home. Look at the
first sentence again. When Sara got to the party, everyone had gone home. Here it means that first everyone went home and then Sara got to the party. Sometimes, one action happens soon after the other action, here we should use the past simple in both clauses such as when Sara got to the party, everyone left, when they saw the police, they ran away, etc.
'
Workers English (WE) and Bourgoise English (BE) are in part an invention for the book, though they do adopt certain grammatical aspects that are observed in real English.
But beware. This is not about real life, and shouldn't be understood as a description of how people do talk or how they should talk.
"Preterite" is "past simple"
In WE language, both the preterite and the past participle are always the same. (unlike in BE, and in real English in which they are sometimes different.)
So in WE the past tense of "I see" is "I seen", and the present perfect is "I've seen". These are both formed from the BE past participle "seen" And in WE the past tense of "I eat" is "I ate", and the present perfect is "I've ate". These are both formed from the BE preterite.
In forming the WE past tense, there are two choices. Either use the BE preterite or use the BE past participle.
In WE "I ate" is the preterite and "I've ate" is the present perfect.
In real English "I ate" is the preterite and "I've eaten" is the present perfect
Best Answer
Broadly, you can consider them as synonyms. This is to make us understand that when you are talking about something that happened in 'past', grammatically you are talking in 'past tense'. And, it is simply past tense without describing any mood or completion of a particular event (or else it then starts having other types of past i.e. past perfect etc.).
Wikipedia says...
Having this said, past tense is actually an umbrella term which covers many things in English grammar. Under past tense, there could be many other types such as past perfect, past participle and so on.
Past tense is generally considered as a Simple Past if you have not specified anything about it.
About.com describes it as a synonym by putting it into brackets. There are also other terms for this mentioned on the same page.