關(guān)聯(lián)詞只能用whether不能用if表示“是否”的情況如下:
A)在表語(yǔ)從句和同位語(yǔ)從句中。例如：
The question is whether the film is worth seeing.
The news whether our team has won the match is unknown.
B)在主語(yǔ)從句中,只有用it作形式主語(yǔ)時(shí),whether和if都能引導(dǎo)主語(yǔ)從句,否則,也只能用whether。例如：
Whether we shall attend the meeting hasn't been decided yet.
It hasn't been decided whether(if)we shall attend the meeting.
C)在介詞之后。(介詞往往可以省略)例如：
It all depends (on) whether they will support us.
D)后面直接跟動(dòng)詞不定式時(shí)。
He doesn't know whether to stay or not.
E)后面緊接or not 時(shí)。
We didn't know whether or not she was ready.
F)引導(dǎo)讓步狀語(yǔ)從句,只能用whether。
Whether you like it or not, you must do it well.
G)用if會(huì)引起歧義時(shí)。例如：Please let me know if you like it.
該句有兩個(gè)意思：“請(qǐng)告訴我你是否喜歡”。
或“如果你喜歡,請(qǐng)告訴我?！庇昧藈hether就可以避免。