【by then與since then的用法區(qū)別? !】在英語(yǔ)學(xué)習(xí)中，"by then" 和 "since then" 是兩個(gè)常被混淆的時(shí)間狀語(yǔ)短語(yǔ)。雖然它們都用于描述時(shí)間關(guān)系，但它們的含義和使用場(chǎng)景有明顯不同。以下是對(duì)這兩個(gè)短語(yǔ)的詳細(xì)總結(jié)和對(duì)比。
一、基本含義
| 短語(yǔ) | 含義 | 使用場(chǎng)景 |
| by then | 到那時(shí)為止（強(qiáng)調(diào)截止時(shí)間） | 表示某一動(dòng)作或狀態(tài)在某個(gè)時(shí)間點(diǎn)之前已經(jīng)完成 |
| since then | 自那以后（強(qiáng)調(diào)從過(guò)去某一點(diǎn)開始持續(xù)到現(xiàn)在） | 表示從過(guò)去某一時(shí)間點(diǎn)開始一直持續(xù)到現(xiàn)在的狀態(tài)或行為 |
二、語(yǔ)法結(jié)構(gòu)與用法
1. by then
- 結(jié)構(gòu)：by + 時(shí)間點(diǎn)（如：by 2020, by next week, by the time I got there）
- 時(shí)態(tài)：通常與完成時(shí)連用
- 例句：
- By the time we arrived, the movie had already started.
- She had finished her homework by then.
> ? 注意：強(qiáng)調(diào)“在某個(gè)時(shí)間點(diǎn)之前”已經(jīng)完成的動(dòng)作。
2. since then
- 結(jié)構(gòu)：since + 時(shí)間點(diǎn)（如：since last year, since he left, since Monday）
- 時(shí)態(tài)：通常與現(xiàn)在完成時(shí)連用
- 例句：
- He has lived in Paris since then.
- We haven't heard from her since then.
> ? 注意：強(qiáng)調(diào)“從某個(gè)時(shí)間點(diǎn)開始一直持續(xù)到現(xiàn)在”的狀態(tài)或行為。
三、常見(jiàn)錯(cuò)誤對(duì)比
| 錯(cuò)誤用法 | 正確用法 | 原因說(shuō)明 |
| I have been waiting here since then. | ? 正確（表示從過(guò)去某一時(shí)間點(diǎn)持續(xù)到現(xiàn)在） | since then 強(qiáng)調(diào)持續(xù)性 |
| I will finish it by then. | ? 正確（表示到那時(shí)會(huì)完成） | by then 強(qiáng)調(diào)截止時(shí)間 |
| I saw him since last week. | ? 錯(cuò)誤（應(yīng)為：I have seen him since last week） | since 不能與一般過(guò)去時(shí)連用 |
| The meeting was over by then. | ? 正確（表示在那個(gè)時(shí)間點(diǎn)前已經(jīng)結(jié)束） | by then 強(qiáng)調(diào)截止時(shí)間 |
四、總結(jié)表格
| 項(xiàng)目 | by then | since then |
| 含義 | 到那時(shí)為止（截止時(shí)間） | 自那以后（持續(xù)到現(xiàn)在） |
| 時(shí)態(tài) | 完成時(shí)（have/has + 過(guò)去分詞） | 現(xiàn)在完成時(shí)（have/has + 過(guò)去分詞） |
| 用法重點(diǎn) | 動(dòng)作在某個(gè)時(shí)間點(diǎn)前已完成 | 動(dòng)作從過(guò)去某一點(diǎn)持續(xù)到現(xiàn)在 |
| 常見(jiàn)搭配 | by the time, by next month, by 2025 | since last year, since he left, since 2020 |
| 典型句子 | She had left by then. | They have been friends since then. |
通過(guò)以上對(duì)比可以看出，"by then" 更注重“截止時(shí)間”，而 "since then" 更強(qiáng)調(diào)“持續(xù)性”。掌握這兩個(gè)短語(yǔ)的區(qū)別，有助于更準(zhǔn)確地表達(dá)時(shí)間關(guān)系，避免常見(jiàn)的語(yǔ)法錯(cuò)誤。
