Joe LEARNED about an epoch in which dinosaurs HAD WALKED the earth WRONG
The Mgmat gives an explanation stating even though the action WALKED took place earlier than LEARNED, past perfect tense should not be applied to WALKED as the sequence of time does not need to be emphasized or clarified.
The rule of using past perfect tense applies when you are comparing two actions. In this case, we are talking about LEARNING of Joe. The part "...an epoch in which..." already refers to the era of dinosaurs, so no use of "had".
The sentence where you need to apply the rule of 'use of had'-
When Joe entered the room, dinosaurs had already finished the cake.
Here, we are comparing two times. The time when Joe's entered & the time when Dinosaurs finished the cake. Moreover, "when" in the above sentence refers to the action of Joe's entrance, so to refer any action earlier to that action, we use 'had'.
Thanks a lot alpe,
I got it now after some practice, when to apply past perfect tense.
Here as you explained we are not applying past perfect because past perfect needs
1 past action 2 past action happened after 1
So 1 can be said to be past perfect i.e. had+past participle(-ed form of verb)
But since its only mentioned dinosaurs walked on earth there is no mention of whether they walked the earth before mighty joe.
So past perfect does not need to be applied.
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