幾點鐘 (或幾時幾分幾秒)、一天當中的某個時間點、一週當中的某個時間點、特別的節日等時間詞的前面須使用 at。例如：
- I’ll pick you up at the airport at six o’clock. (我六點鐘會到機場接你)
- I woke up from a dream at 4:30 a.m. (我凌晨四點半從夢中醒過來)
- He was released/discharged from (the) hospital at midday. (他中午出院)
- What are you doing at the weekend? (你週末要幹什麼？) － 美式英語通常使用 on the weekend。
- John works at (the) weekends. (約翰每個週末都工作) －美式英語通常使用 on (the) weekends。
- Mary will meet her pen pal at Christmas. (瑪麗將在聖誕節和她的筆友見面)
- At the Lunar New Year, the Lion Dance is one of the most popular traditional performances. (在農曆新年，舞獅是最受歡迎的傳統表演之一)