"with a positive mood," 1947, apparently from on the upbeat "improving, getting better," attested from 1934 and a favorite of "Billboard" headline-writers in the early 1940s, from the musical noun upbeat (1869), referring to the beat of a bar at which the conductor's baton is in a raised position; from up (adv.) + beat (n.). The "optimistic" sense apparently for no other reason than that it sounds like a happy word (the musical upbeat is no more inherently "positive" than any other beat).
雙語例句
1. Neil's colleagues say he was actually in a joking, upbeat mood.
內爾的同事們說他實際上在說笑逗樂，心情不錯。
來自柯林斯例句
2. Scientists remain upbeat about the information that will be gathered.
科學家對即將收集到的信息仍滿懷希望。
來自柯林斯例句
3. The Defense Secretary gave an upbeat assessment of the war so far.
國防部長對目前的戰事給予了樂觀的評價。
來自柯林斯例句
4. The tone of the speech was upbeat.
這次講話的語氣頗為樂觀。
來自《權威詞典》
5. The Chancellor's upbeat message that the Government had licked inflation for good was marred by more job losses.