Practicing past perfect tense, a student wrote:
I had arrived at the cinema before the movie started.
This felt (and still feels) strange to me, but I can’t figure out why. It is perfectly clear and follows the general rule of tense sequences. I would naturally say I arrived at the cinema before the movie started, because the sequence of events is clearly indicated by before.
The only reason I can think of for the strangeness is that we rarely use past perfect in the main clause of a sentence. But does that mean we never do?
I have less problem with more context:
My friends always teased me for being late for everything, but here I was. I had arrived at the cinema before the movie started.
I also have less problem with reversing the halves of the sentence:
Before the movie started, I had arrived at the cinema.
or the equivalent:
The movie started after I had arrived at the cinema.
(Though in each case, I would probably omit had.)
The main exception is when a main clause in past perfect is followed by a result, introduced by so:
I had arrived at the cinema before the movie started, so I saw all of it.
This can be reworded as the entirely unproblematic:
Because I had arrived at the cinema before the movie started, I saw all of it.
Because I couldn’t explain what was wrong with it, or even if it was wrong, I said to the student that I’d tick his sentence. I’ve looked at several sources since, and can’t find an explanation of exactly this. Even the monumental Cambridge Grammar of the English Language doesn’t seem to cover this. The only thing relevant is a short section titled Omissibility of the perfect, which includes:
Under certain conditions the perfect may be omitted with little or no effect on the temporal interpretation[, especially] in a subordinate clause following … after, as soon as, or before.
That would rather refer to the opposite scenario:
I arrived at the cinema after the movie (had) started.
My general experience is that American English speakers tend to omit the perfect more than speakers of other varieties, but I can’t find any references to confirm that.
Another issue is the relative time span, importance and semantic weight of the two halves of the sentence. The longer and more important the situation in the time clause, the less likely we are to omit the perfect.
Note that omitting the perfect doesn’t always mean simply omitting had:
the movie had started > the movie started (regular verb)
the movie had begun > the movie began (irregular verb)
Lurking at the back of my mind is the sentence:
I arrived at the cinema before the movie had started
which makes sense and sounds natural, but doesn’t follow the sequence of tenses. But Google Ngrams shows before the war had begun/ended and before the sun had risen/set, so it’s not impossible. Even then, those phrases are less common than before the war began/ended and before the sun rose/set.