1. at the invitation of sb． 應某人邀請
eg.: We attended their wedding at the invitation of Mary.
我們應瑪麗的邀請參加了他們的婚禮。
2. at the latest 最遲、最晚
at the latest副詞作狀語。
eg.: You'll have to be at the airport by 8:35 at the latest.
您最遲必須在8點35分前到機場。
我會巧辨析：latter adj．意思是指（兩者中）後者的，後者，反義詞是former,（兩者中）前者。注意，不要把latter與late的比較級later混淆。late adj. & adv．遲，遲的，晚的，晚期，在晚期；latest adj.& adv．為late的最高級。意思是最新、最近或最遲，at the latest最遲、最晚。later adj. & adv．為late比較級，意指較遲，較晚一些。
3. at the risk of 冒著……的危險
eg.: He is at the risk of failing because of his low scores.
他因為低分而有不合格的危險。
4. at the same time 同時
eg.: The colors were at once bold and lovely at the same time.
色彩同時是既顯眼且美麗的。
我會巧辨析：in time及時；on time準時；at the same time同時；at atime一次，每次。
5. at the sight of 看見
eg.:She turned away in horror at the sight of so much blood.
她一看見這麼多血就立刻嚇得轉過臉去。
我會巧辨析：at the sight後面不接賓語；at the sight of一看見……就；in sight of在視線內；out of sight視線外。
6. at the speed of 以……的速度
eg.: Moving at the speed of life.
人命關天，分秒必爭。
at the thought of 想到
at the thought of介詞短語，後接名詞、動名詞、代詞等。
eg.: Jenny smiled at the thought of the evening ahead.
珍妮因之前那個晚上的想法笑了。