Translation:A millennium is not a century.
The millennium is not the century. - tại sao lại sai? Câu hỏi như đánh lừa vậy, Đáng lẽ phải ra đề là: Một thiên niên kỳ không phải là một thế kỷ.
we were told from the start that if there is not a "mot" in front of the word, then it is "the". Now they are changing the rules with no explanation. Just please explain, is all.
My guess is one of those exceptions. "The millennium.." refers to a specific one and "A millennium..."refers to it generally. That's how I guessed this one.
Yes, the lack of explanations and the loss of vocabulary creates only frustration and the sense you're spinning your wheels here--memorizing "right answers" to put down isn't really learning. I started to answer "a" or "one" then thought exactly as you, 'must be the'.