Hello Grammar exchange members!
Please consider the following sentence from Naomi Shihab Nye's essay titled "Field Trip".
(a) By the time our workshops ended that summer, we felt more deeply bonded than other groups I'd known.
The knowledge that I have about the "by the time" adverb clause is that it is used with either the past perfect or future perfect in the main clause like the example sentences below.
(b) By the time I arrived at the party, everyone had already left.
(c) By the time I arrive at the party, everyone will have already left.
But in sentence (a) the past perfect isn't used in the main clause. Also, I'm wondering if I can replace "by the time" with "when" in sentence (a).
Thanks in advance.