Mathematics Senior High about 5 yearsago

この文章の訳に〜よりが使われる理由を教えてください🙏

【3】本文の内容に合う文はTを, 合わない文はFを [ ]に入れなさい。 1. In junior high school, Mari preferred reading foreign literature to listening to Japanese pop idol music. 2. Around Mari there were no students who felt passionate about foreign literature. I 」

Mathematics Senior High almost 9 yearsago

at that timeとthenの意味で「その時」という意味ですが、使い方の違いを教えて下さい🙏