I've started playing a visual novel and came across this sentence in the first minute of, in lack of a better term, gameplay.
I know that this roughly translates to:
Although the school's armed forces left 2 weeks ago, there's still no sign of them returning. I wonder if they're alright.
The problem I have is with the tense. My teacher taught me that Japanese tense is realised by the last verb in the sentence. So why does たつ take たった here?