I was solving a question for TOEIC prep, and found this sentence. The question was
"The River Thames last ______ over three decades ago."
The book says the answer is number 2 because the structure of the sentence goes like:
The River Thames(subject) last(adverb) _______(verb) over three decades ago.
However, somehow the placement of the adverb in the sentence feels so foreign. I mean, it is a foreign language to me, but this feels unusually foreign to me. Isn't there a certain rule to place adverb in a sentence? or you can place it anywhere?