since、for、during、while：時間字不再讓你流淚

"I've been waiting since three hours." 痛，但超常見。還有 "during I was eating, the phone rang." 兩句裡頭的時間字在你腦中聽起來都還行，但落到母語者耳裡就不對勁。修正只要一點點。我們來清乾淨。

快速解答

• since = 過去的一個起始點。（since Monday、since 2019）
• for = 一段時間長度。（for two hours、for three years）
• during = 在一個事件或名詞片語之內。（during the meeting、during summer）
• while = 在一個有動詞的子句之內。（while I was eating）

如果下一個字是時間的一個點 -> since。如果是數字 + 單位 -> for。如果是描述一個事件或時段的名詞 -> during。如果是一個有主詞和動詞的小完整句 -> while。

核心規則

• since + 起始點：告訴你某件事何時開始。幾乎都搭配現在完成式或過去完成式。"I've worked here since January."
• for + 持續時間：告訴你某件事持續多久。幾乎任何時態都可以用。"I worked there for five years."
• during + 名詞片語：告訴你在哪個時段或事件之中。"I fell asleep during the movie."
• while + 主詞 + 動詞：告訴你與另一個動作同時。"I fell asleep while the movie was playing."

最後兩個是兄弟，不是雙胞胎。during 後面接一個東西（事件、時段）。while 後面接一個句子（有它自己的主詞和動詞）。很多學習者試著互換，這就是這整家族最大的漏水點。

真實例句

起始點 —— since

• I've lived in Taipei since 2018.
• She hasn't called since Monday.
• We've been friends since elementary school.

時間長度 —— for

• I lived in Taipei for five years.
• She talked for an hour without stopping.
• We've known each other for ages.

在某個事件或時段之內 —— during

• My phone rang three times during the meeting.
• He traveled a lot during the summer.
• Nobody moved during the earthquake.

與另一個動作同時 —— while

• My phone rang while I was presenting.
• He read three novels while he was on vacation.
• Nobody moved while the building was shaking.

注意 during / while 這一對對齊得多乾淨：意思不變、只換後面接的東西。During the meeting = 一個名詞。While I was presenting = 一個子句。同樣的意思，兩個不同的文法位置。

常見錯誤

• "I've been waiting since three hours." → "I've been waiting for three hours." · 三小時是*長度，不是起始點。中文「等了三小時」直譯成 since 就出包。*
• "I lived in Korea since five years." → "I lived in Korea for five years." 或 "I've lived in Korea since 2020." · since 後面要接時間的一個點，不是持續時間。
• "During I worked there, I met my best friend." → "While I worked there, I met my best friend." · during 後面不能接子句。
• "While the meeting, my phone rang." → "During the meeting, my phone rang." · while 後面不能只接一個名詞。
• "He stayed for since Monday." → "He has stayed since Monday." 或 "He stayed for three days." · 挑一個——since 或 for，不能兩個都用。

一個細微的時態細節：since 幾乎都會拉出完成式（"I have lived... since..."），因為你描述的是一段從過去開始、延續到現在的時間。for 比較有彈性——簡單過去式（"I lived there for five years, then moved"）、現在完成式（"I've lived here for five years"）、未來式（"I'll be there for two weeks"）都可以。如果你的句子用 since 配簡單過去式動詞，最好再確認一次；通常它要的是現在完成式。

考試陷阱

閱讀和聽力部分很依賴這一家族，因為這些字對學習者來說看起來可以互換，對母語者來說卻鎖死了精確的意思。TOEIC 和 IELTS 都喜歡這種句子："The number of applicants has tripled ___ the new policy took effect." 如果你伸手去抓 during，你會丟分——"the new policy took effect" 是一個完整的子句，所以這個空格要 since（把它當成起始時刻）或 after。TOEFL 聽力常把這個藏在敘事回顧裡，講者會在同一段裡頭從「during my internship...」切到「while I was interning...」。兩個說法描述同一段時間，但一個後面接名詞、另一個後面接子句——理解題可能會默默確認你能不能把一個改述成另一個。

小試身手

1. I've been studying Japanese _____ I was twelve.
2. She lived in Berlin _____ almost a decade.
3. Please turn off your phone _____ the performance.
4. My laptop crashed _____ I was saving the file.
5. We haven't seen each other _____ the last conference.

解答

1. since — "I was twelve" 是過去的一個起始點。
2. for — "Almost a decade" 是一段持續時間。
3. during — "The performance" 是一個事件（一個名詞片語）。
4. while — "I was saving the file" 是一個有自己主詞和動詞的子句。
5. since — "The last conference" 是過去的一個特定時點。

一句總結

問自己一個問題：下一個字是哪一類東西？ 時間的一個點、一段持續時間、一個事件，還是一個完整的小句子？對上了，你的時間字就不會再漏水了。