Hi I am confused with a few verb tense questions, can someone help me with it?
Q1: from OG11
His Studies of ice-polished rocks in his Alpine homeland, far outside the range of present-day glaciers, led Louis Agassiz in 1837 to propose the concept of an age in which great ice sheets had existed
in now currently temperate areas.
I don't understand why "had existed" needs to be changed to simple past tense "existed"? I understand the "now currently" is a redundant expression.
Q2: from OG11
A 1972 agreement between Canada and the United States reduced the amount of phosphates that municipalities had been allowed
to dump into the Great Lakes.
Here the OG explains that "had been allowed" shouldn't be used because municipalities is still allowed to dump phosphates in to the lake today. Therefore "are allowed" should be used.
But I still don't understand, isn't the law "reduced" the amount "had been allowed" to dump?
I thought when there is a past tense, we should use "had..." to indicate an event precedes it?