英文文法專題系列文章:
If假設語氣用法攻略
If假設語氣用法攻略
whether 4 大用法 ＋ 文法分析
whether 4 大用法 ＋ 文法分析
「介詞+which」用法規律
Besides or Except? 用法
Besides or Except? 用法
Even的九大用法
目錄
Since的用法
Since分別有兩種涵意：時間和原因。我們可以依照句子語意、結構和時態，決定since在句子中的意思。
1. 時間
在時間的層面上，與「自從」有相似的意思。Since通常可作為介系詞代入一個片語、或連接詞代入一個子句、或是以副詞單獨存在。另外，since後的子句大多是過去式，主要子句為完成式。
連接詞
當since用作連接詞時，可搭配一段期間或某個時刻，引導時間附屬子句，意為「自從…」。附屬子句，即 since 子句，的動詞通常為過去簡單式或現在完成式，而主要子句則使用現在完成式或過去完成式，但以現在完成式居多。如要表示一段期間，since子句該為現在完成式；如要表示某個時刻，since子句便為過去簡單式。不論是過去簡單式還是現在完成式，意思大致上相同。
【例】I haven’t done any outdoor activities since I graduated from university.
【例】John had been cooking his own dinner since he was twelve years old.
在另一種清況下，當主要子句的結構為”It + be + 時間 + since”，可以以四種不同的句型構成，但意思絕對相同。主要子句的be以現在簡單式 is或現在完成式 has been，而附屬子句則為過去簡單式或現在完成式。在美式英語中，” It has been… since…” 比較常見。
【例】It is ten months since Paul and Linda moved to a new apartment.
【例】It is ten months since Paul and Linda have moved to a new apartment.
【例】It has been ten months since Paul and Linda moved to a new apartment.
【例】It has been ten months since Paul and Linda have moved to a new apartment.
其實在剛剛説明的結構中，be亦可使用過去簡單式 was 或過去完成式 had been，但此時 since 子句須使用過去簡單式或過去完成式。
【例】It was ten months since Paul and Linda moved to a new apartment.
【例】It had been ten months since Paul and Linda had moved to a new apartment.
當 since 不是引導過去某個動作或事件，而是過去的某個狀態並現在一直持續著 ，主要子句及其附屬子句都要用現在完成式。
【例】Tom has been sleeping less than 4 hours every day since he has become a doctor.
副詞
作為時間副詞，since/since then有著「此後，從此，自那以後」的意思。
而ever since能用來加強since和since then的語氣。
【例】We graduated from secondary school a year ago and we haven’t reunited since/since then.
【例】They divorced few months ago and haven’t contacted each other ever since.
介系詞
作為介系詞時，since只能與某一時刻搭配，即是since之後必須接著日期、年份等時間有關的詞。時刻能以副詞（e.g. yesterday）、名詞片語（e.g. the beginning of the match）或動作動詞（e.g. I left）表示。意為「自從…，自…以來，從…至今」。
【例】Since yesterday, I haven’t eaten anything.
【例】Since the beginning of the match, she has been cheering loudly for her teammates.
【例】Since I left my previous workplace, it has become much quieter than before.
在某種情況下，我們可以將since從連接詞變成介系詞—就是當 since 子句和主要子句的主詞（subject）是相同時，便可省略 since 子句的主詞。這樣，本身句中的主動詞須改為動名詞 ，接在since後。
【例】Since attending tutorial classes, I have become more confident when answering questions during lessons.
（原句：Since I have attended tutorial classes, I have become more confident when answering questions during lessons.）
2. 原因
除了在時間方面，since 亦可作為連接詞，引導表示原因的附屬子句，意為「既然」。Since接著的子句通常是現在式，亦能是整個前後子句都為過去簡單式。放在主要句子前或後都同樣沒問題。Since的運用大多想表達顯而易見或已成事實的原因。
【例】Since it is too cold out there, I will just stay home today.
【例】Since the power is out, we should just go to bed directly.
英文文法小測 — since用法
第一部份：填充題
- She has been waiting (since/for) 8am.
- John has been playing video games (since/for) hours.
- Dave and Sandy have been friends (since/for) nine years.
- They haven’t done any house chores (since/for) Christmas Eve.
- I have become a vegetarian (since/for) last October.
第二部份：選擇題
請選出since在以下句子中的涵意。（時間/原因）
- I am going to wear wellies since it is raining outside.
- Since no one is paying attention to the TV, I should just turn it off.
- I submitted my dissertation few days ago and I haven’t turn on my computer since then.
- My annual income hasn’t increased since 2016.
- We are going to the beach since today is hot and sunny.
答案請參考文章結尾。
其他詞能取代since嗎？
1. Since vs. For
Since和for同為時間介系詞，適用於完成式的句子，表達某人已做了某件事或處於某個狀況一段持續的時間。可是，它們的用法有些不同，所以for是不能替代since。接著，讓我們看看應如何區分since和for。
- Since + 特定時間點（point of time）：表示當事件發生在某個時刻時
【例】She has lived with her husband since she got married.
【例】I have stopped drinking milk since three years old.
- For + 時間長度（length of time）：表示當事件持續了一段時間
【例】She has lived with her husband for five years.
【例】I have stopped drinking milk for ten years.
2. Since, Because,
As
Since，because 和as都可解作「因為」，用法大致上相同。唯一少許的差異在於它們的語氣。Because的語氣最強，其次是since，as算是最溫和。
Since及as用作對已知的事實提供理由和原因，並非表示直接原因，視附屬子句（since/as子句）為附加資料。還有，通常since和as的子句會加上逗號，將原因和主要子句分開，降低原因的重要性。Since的語氣比as稍為強一點和正式一點。
Because則是表示直接原因，強調原因。適合用於回答why的問題，以及引導從句。
英文文法小測 — since用法答案
第一部份：填充題
- She has been waiting since
- John has been playing video games for
- Dave and Sandy have been friends for nine years.
- They haven’t done any house chores since Christmas Eve.
- I have become a vegetarian since last October
第二部份：選擇題
- I am going to wear wellies since it is raining outside. 原因
- Since no one is paying attention to the TV, I should just turn it off. 原因
- I submitted my dissertation few days ago and I haven’t turn on my computer since then. 時間
- My annual income hasn’t increased since 2016. 時間
- We are going to the beach since today is hot and sunny. 原因
想挑戰更多更深題目？關於since用法的TOEIC仿真題必定適合不過！有興趣的話請參考以下片段：
英文文法專題系列文章:
If假設語氣用法攻略
If假設語氣用法攻略
whether 4 大用法 ＋ 文法分析
whether 4 大用法 ＋ 文法分析
「介詞+which」用法規律
Besides or Except? 用法
Besides or Except? 用法
