在我们的不少语法学著作中和英语学家的论述中,尤其是在中学英语教学中,仍然存在这样 的观点:在表示“是否”这个意义时,if与or not不可并用。例如:“I asked him if he knew or not.”这个句子,许多人就认为if用错了,应改用whether,或删去or not。
然而,事实上,上述观点是不符合现今英语的实际使用情况的,也是与英美语言学家的论述 相违背的。?
美国语言学家J•H•Eugene明确指出:“Or not is sometimes used at the end of clauses introduced by whether and if.”
下面是从美国的语法著作中摘引的两个例句:
I don't care if you come or not.
She asked me if I was going to the store (or not).
英国语言学家们也认为,在动词的宾语从句中if…or not是规范的用法。英国著名语言学家 R•Quirk等人就曾举过这样的例子:
I don't care if your car breaks down or not.
He didn't say if he'll be staying here or not.
在其他英语语法著作、辞书和文学作品 中,也常常可以看到这种用法,例如:
He asked if I wanted to insure my luggage or not.
I don't know if I can come or not.
Let me know whether (if) you can come or not.
She did not know if he was right or not.
有些语言学家明确指出,在许多宾语从句中,if…or not和whether…or not是可以互换的 。例如:
I wonder if (whether) you've met him (or not).
I don't know if (whether) I'm going to answer it or not.
I can't tell you if (whether) he's coming or not.
综上,我们可以说,if是可以与or not 并用的,在动词的宾语从句中,whether…or not与 if…or not也是可以互换使用的。
此外,后置的主语从句,也可以用if…or not引出。例如:
It's still uncertain if (whether) he's come or not.
至于不可使用if…or not的情况,则应注意下列几点:
1. 当主语从句位于句首时,不可使用if…or not,而应用whether…or not。例如:
Whether it rains or not doesn't concern me.
2. 当宾语从句位于主句之前时,也只能使用whether…(or not),不能使用if…(or not)。例如:
Whether you have met Georger Lamb or not,I can't remember.
3. 当一个动词不定式(短语)充当动词的宾语时,只能使用whether…(or not),不可使用if …(or not)。例如:
He doesn't know whether to stay or not.
4. 表语从句、同位语从句应使用whether…(or not),不可使用if…(or not)。例如:
My question is whether he left (or not). I have a question whether he left (or not).
5. 从句充当介词宾语,应使用whether…(or not),不可使用if…(or not)。例如:
I am anxious about whether he will come or not.
还应注意: or not可直接跟在whether 后面,即whether or not,但不能直接跟在if后面,即不可说if or not。例如:
I don't care whether or not your car breaks down. Please tell me whether or not you agree.?
上述二句均不可把whether换为if。