to V和Ving的差別

If you don't feel comfortable doing ....
這裡的doing...是[分詞片語]當述部don't feel comfortable的修飾語,屬於副詞性質,你在doing的前面加上while來檢驗,就可以體會其作用了.

這裡不能用不定詞to do...,因為不定詞表示目的(尚未作),你在不定詞前面加上in order,就可知道不能用了.

2011-11-12 13:34:48 補充：
分詞在當修飾語時，時間點與主要子句的動詞相同。不定詞在當修飾語時，時間點比主要子句的動詞晚。

2011-11-12 14:58:22 補充：
if you want後面接的是受詞，屬名詞性質，不能當副詞性質的修飾語，用while和in order to來檢驗。want是及物動詞。

"doing"在此句中是屬於動名詞，而不是現在分詞，所以可以跟"to do"互換。

If you don't feel comfortable doing this, I won't push you.

If you don't feel comfortable to do this, I won't push you.

兩句意思都是一樣的。


但並不是所有情況下都可以用"doing"代替"to do"，比如：

If you come to school to study ... =/= If you come to school studying ...
I went to the store to get some milk =/= I went to the store getting some milk

2011-11-12 01:46:51 補充：
首先很抱歉的說一聲，對於那一大堆文法用詞我真的不太懂要怎麼解釋。但簡單點來說，當 "to do ..." 與 "doing ..." 代表的都是名詞片語，也就是說在句中是被當作名詞看待時，"to do" 和 "doing" 互通。

如果你想知道"to do / doing"是否屬於名詞片語，可以用"what"一詞去倒裝：

- If you don't feel comfortable to do this
- if you don't feel comfortable doing this
- if "what" you don't feel comfortable is ... (通!)

2011-11-12 01:48:09 補充：
- if you come to school to study
- if you come to school studying

- what you come to school is "to study" (通!)
- what you come to school is studying (不通!)

所以只能用"to V"不能用"V-ing".

2011-11-12 01:51:50 補充：
- if you want to go to school
- if you want going to school

- if what you want is "to go to school" (通!)
- if what you want is "going to school" (通!)

"to V" and "V-ing" 可以互用。

2011-11-12 02:57:24 補充：
關於“副詞片語”的應用，請參考 http://www.cybertranslator.idv.tw/grammar/adverbs.htm

副詞片語是可以放在句尾的。