VOA慢速英语:Inventors Given Hope on Business Method Patents

whether

if和whether通用，都表示“是否”的意思。一般来说，后者比较正式，在口语中前者常用来代替后者。但两者有时具有不同的暗示。用

whether时，正反两面的选择意义较强，问话人并不在意回答是肯定还是否定；而用if时，则比较强调单方面，即正面，问话人希望得到肯定的回答。另外，还要注意以下几点：

一、whether和if都可以与or not连用；但写在一起时，只能用whether，不能用if。如：

    I don't care whether (或if) it will rain or not．

I don't  care  whether  or  not  it  will  rain.  (不用if)

二、在引导宾语从句时，应注意：

1、表示“是否”时，两词都能引导宾语从句。

I wonder if/whether you can examine him now．

2、宾语从句移置句首时，用whether，不用if。

Whether it is true or not， I can't say．

3、宾语从句为否定形式时，通常用if，而不用whether。

I asked Tom if Mary  wouldn’t come．

4、作discuss等词的宾语，用whether不用if。

We discussed whether we should buy the gift for him．

三、在下列情况下，只能用whether，不能用if。

1、与不定式连用时，只能用whether．

    He can't decide whether to accept or refuse．  

    2、在介词后，只能用whether。

    Everything depends on whether he is ready．  

    3、在名词后作同位语时，只能用whether。   

The question whether they ought to stop working was discussed among the workers．

I have no idea whether he is there． 

    4、引导主语从句时，只能用whether。

    Whether  he comes or not doesn't concern me．

    5、引导表语从句时，只能用whether。

    What Maria doesn't  know is whether there will be enough snow．  

四、if可引导条件状语从句，译作“如果”，whether可引导让步状语从句，译作“不管、无论”。

If I were you，I would not buy．

Whether he agrees or not，I shall go there．

2.The Supreme Court has said, for example, if Albert Einstein determined that E = mc squared -- which he did -- he never would have been able to get a patent on that. That's too abstract.

would have been虚拟语气，与过去的事实相反。

3.You can have that test, but it can't be an exclusive test because of the nature of the patent laws which are to protect new and unknown inventions.

can't be情态动词的否定

cannot或can’t

    表示“不能够”“不可以”和“不可能”。如：
    1.I cannot answer your question at present.我目前无法回答你的问题。
    2.—Can I leave now？我可以走了吗？
    —No, I am afraid you can’t.对不起，恐怕不行。
    另外，cannot还用于固定习语中。如： 
    She cannot help laughing. 她禁不住笑了。
    I cannot but try again. 我不得不再试一次。
    You cannot be too careful. 你越小心越好。