Soon 意為「不久」、「很快地」。就「不久」的意思而言，soon 可以指現在之後的不久 (亦即未來或過去的未來) 以及過去某個時間點之後的不久。與其他許多短副詞一樣，soon 可用在句首、句中和句末，但在指過去某個時間點之後不久的句子中，soon 不可用在句末。例如：
- The winter is coming. Soon it will be Christmas. (冬天來了。耶誕節很快就要到了) (句首位置)
- I soon realized the mistake. (我很快就意識到了錯誤) (句中位置)
- Peter will soon be here./Peter will be here soon. (彼得很快就到) (句中或句末位置，指未來)
- Mom phoned to say she’d be home soon. (媽媽打電話說她很快就回家) (句末位置，指過去的未來)
- A: Bye for now! (A：再見！)
B: Bye. See you soon! (B：再見。一會兒見！) (句末位置，指未來) - Soon all the Mayday concert tickets were sold out. (五月天演唱會門票瞬間秒殺) (正)
- All the Mayday concert tickets were soon sold out. (正)
- All the Mayday concert tickets were sold out soon. (誤)