請問一題英文：whether 及 if 當〝是否〞通用嗎？

Question

一直認為，引導名詞子句的whether (or not)及 if當是否，且用法相同，可互換。但是以下這一題題目：

_______ he can get up on time is a problem.

答案是：Whether

選項中也有 If 但是解答並不採用 If
請問為何不可以使用 If，If 在引導名詞子句的時候有限制嗎？
難道不能引導名詞子句當主詞嗎？
麻煩解答了。
謝謝

Answer 1

whether與if可以通用的狀況只有一種:

在非正式場合(1)引導名詞子句(2), 當成動詞的受詞(3).
三個條件缺一不可.

I don't know whether(or "if") she will come (or not).

再進一步說明的話, 以下狀況都不能以if取代:

1. whether引導副詞子句(無論...或...):
I won't go whether she goes or not.

2. whether引導名詞子句, 當成主詞/主詞同位語/主詞補語:
Whether he can get up on time(主詞) is a problem.
(這就是版主所問的句子)
It is up to you whether you join us or not(主詞).
(it是虛主詞)
The question whether she did it or not(主詞同位語) is still unanswered.
What I am concerned about(主詞) is whether you are happy or not(主詞補語).

3. whether引導名詞子句, 當成介系詞(常省略)的受詞:
I am not sure (of) whether he can do it or not.
It depends (on) whether you have enough money or not.
I am so worried about whether Jane can past the test or not.

4. whether後接不定詞, 構成名詞片語:
My problem is whether to keep waiting or just leave.

5. 有可能造成語意混淆時:
Let me know whether you are coming.
告訴我你到底會不會來.
Let me know if you are coming.
如果你要來, 告訴我一聲.


2007-05-07 05:22:52 補充：
...whether Jane can "pass" the test or not.

2007-05-07 23:56:01 補充：
Hi Kenny,
You can say that again.
Yet people always cannot help doing something for a change, otherwise life could've been too boring to live.

Answer 2

Hi, Kevin大大
這樣看來
用''Whether'' 是最保險的選擇了
是嗎?

2007-05-08 17:41:50 補充：
Good point.^_^

Answer 3

if跟whether可以帶出副詞子句
兩個的用法也可以說是大同小異
但是這裡要注意!
if不可以帶出名詞子句
只有whether可以!