§ 語氣助動詞 ought to 的用法: 1. ought 表示義務、責任,或應該,指現在或未來的時間。 He ought to feel ashamed of himself. (他應該感到慚愧。) You ought to leave early tomorrow morning if you want to catch the first train. (如果要趕上第一班火車,明天早上你就得早走。) 2. ought to have / should have + 過去分詞: 表示「過去該做而未做的事」。 We ought to have left for Tokyo before 10 o'clock last night. (我們昨晚應該在十點前前往東京的。) <本句所表達的是「但是我們沒這麼做」> ought to have / should have + 過去分詞亦可表示 「推測截至目前為止已完成的動作」。 The department store ought to have been close now. (百貨公司現在應該已經打烊了。) 〔注意〕ought to 只用來表示現在時態,而沒有過去式。 〔補充〕否定句句型如下: 主詞 + ought not (= oughtn't) to+V(某人不應該…) You ought not to tell a lie.(你不應該說謊。)