名詞子句：that / whether / if / wh-Noun Clauses

一整個子句，放在名詞的位置

名詞子句就是「一個句子當名詞用」，可以出現在主詞、受詞、補語的位置。國中學過的間接問句（I don't know where he lives.）其實就是 wh- 名詞子句。三種開頭：that 帶出一個陳述（「……這件事」），whether / if 帶出是非問題（「是否……」），wh- 詞帶出疑問詞問題（「什麼、誰、哪裡、為什麼……」）。不管哪一種，子句內部都用直述句語序：主詞在前、動詞在後。

• I believe that honesty is the best policy.我相信誠實是上策。（受詞）

• Nobody knows whether the typhoon will hit Taiwan.沒人知道颱風會不會侵台。（受詞）

• What you said yesterday really hurt her.你昨天說的話真的傷了她。（主詞）

• The problem is that we don't have enough time.問題是我們時間不夠。（補語）

三種名詞子句比一比

if 只能當及物動詞的受詞；放句首當主詞、當介系詞受詞、後面接 or not 緊跟在後、或接不定詞（whether to go）時，都只能用 whether。

虛主詞 It is … that 與 the fact that

that 子句當主詞會讓句子頭重腳輕，英文習慣把它移到句尾，前面用 It 佔住主詞的位置：It is clear / important / surprising that…、It seems that…。介系詞後面不能直接接 that 子句，要借 the fact that 當橋樑；the fact、the news、the idea、the belief 後面接的 that 子句叫同位語子句，用來說明「這個事實／消息／想法是什麼」。

• It is surprising that so many students chose to study abroad.這麼多學生選擇出國念書，令人驚訝。

• It seems that the new policy has made little difference.新政策似乎沒帶來什麼改變。

• Despite the fact that it was raining, the concert went on.儘管下著雨，演唱會照常進行。

• The news that our team had won spread quickly.我們隊贏了的消息很快傳開。

同位語 that 和關係代名詞 that 怎麼分

看 that 後面是不是一個完整的句子。同位語子句本身完整，that 不當任何成分，只說明前面名詞的內容，不能換成 which；關係子句缺了主詞或受詞，that 在子句裡代替前面的名詞，可以換成 which。

• The idea that we should cancel the trip upset everyone.我們應該取消旅行這個想法讓大家很失望。（同位語：子句完整）

• The idea that he suggested was rejected.他提出的點子被否決了。（關代：suggested 少了受詞）

常見錯誤

• ✗I don't know where does he live.
  ✓I don't know where he lives.名詞子句用直述句語序，不用疑問句的助動詞倒裝。
• ✗If he will come is still uncertain.
  ✓Whether he will come is still uncertain.名詞子句放在句首當主詞時只能用 whether，不能用 if。
• ✗Is important that we save energy.
  ✓It is important that we save energy.中文說「重要的是……」不需要主詞，英文一定要有主詞，用虛主詞 It 佔位，真正的主詞 that 子句放句尾。
• ✗Despite that it was late, he kept working.
  ✓Despite the fact that it was late, he kept working.介系詞 despite 不能直接接 that 子句，要用 the fact that。
• ✗What he wants are a quiet place to study.
  ✓What he wants is a quiet place to study.what 子句當主詞，視為單數，動詞用 is。