Would 最常用於條件句。它也用作 will 的過去式來表示「過去的未來式」(future in the past)。此外，would 亦可表示過去不斷重複或重複很多次的動作或情況。若要瞭解更多 would 在條件句及過去的未來式中的用法，請參閱「條件句」的文法教學、有關「過去的未來式」的文法問題與解答以及 Would Always 的用法說明。
例句：
- If Rachel were rich, she would buy a plane. (如果瑞秋富有，她會買一架飛機) － 條件句
- I knew that Sam would be very successful in his career. (我知道，山姆的事業將會飛黃騰達) － Will 的過去式 (過去的未來式)
- I would always forget my homework, until the teacher threatened to punish me. (我過去老是忘了家庭作業，直到老師揚言要處罰我) － 過去不斷重複的動作或情況
Would 的主要用法
| Would 的用法 | 肯定句 | 你也可以用 |
| 條件句 | 現在：If I were president, I would raise the minimum wage significantly. (如果我是總統，我會大幅提高基本工資) 過去：If I had been president, I would have raised the minimum wage significantly. (如果我是總統，我會大幅提高基本工資) 未來：If I were elected president next year, I would raise the minimum wage significantly. (如果我明年當選總統，我會大幅提高基本工資) | |
| Will 的過去式 (過去的未來式) | My father said he would help me with the mortgage. (我父親說他會幫我還抵押貸款) Sam told me he would be there before 9:00. (山姆對我說，他九點之前會到那裡) | |
| 過去不斷重複的動作或情況 | When I was a kid, I would always go to my Grandma's house. (小時候我常去我外婆家) When he was young, he would always go to clubs. (他年輕時常去夜店) | used to |
| Would 的用法 | 否定句 | 你也可以用 |
| 條件句 | 現在：If I were president, I would not raise taxes. (如果我是總統，我不會增稅) 過去：If I had been president, I would not have raised taxes. (如果我是總統，我不會增稅) 未來：If I were president, I would not sign the tax increase next week. (如果我是總統，下週我不會簽署增稅案) | |
| Will 的過去式 (過去的未來式) | My father said he wouldn't help me with the mortgage. (我父親說他不會幫我還抵押貸款) Sam told me he would not be there before 9:00. (山姆對我說，他九點之前不會到那裡) | |
| 過去不斷重複的動作或情況 | When I was a kid, I would rarely go to my Grandma's house. (小時候我很少去我外婆家) When he got older, he would never go to clubs. (他在年紀稍大時就不去夜店了) | used to |