BBC news 2010-01-22 加文本

1.Jack Straw, who was British Foreign Secretary at the time of the Iraq invasion, has said he could have prevented Britain's participation in the war.

he could have prevented 是虚拟语气:

1)could (不能用 can) have done 表示“过去本能够做某事却未做。”注意：其否定形式 couldn't have done 没有虚拟语气的用法，couldn't have done 只能表推测，相当于 can't have done，意为：“过去不可能做了某事。”

2)should have done 表示“过去本应该做某事却未做。”其否定结构 shouldn't have done 表示 “过去本不该做某事却做了。”

3)ought to have done 表示“过去本应该做某事却未做。”其否定结构 oughtn't to have done 表示 “过去本不该做某事却做了。”

4)need have done 表示“过去本有必要做某事却未做。”其否定结构 needn't have done 表示 “过去本没必要做某事却做了。”

5)might (不能用 may) have done 表示“过去本可以做某事却未做。” 注意：其否定形式 might not have done 没有虚拟语气的用法，might not have done 只能表推测，相当于 may not have done，意为：“过去可能没有做某事。”

2.Whatever the policy of the United States, which as it happens was for regime change as a purpose of foreign policy, that was off the agenda as far as the United Kingdom was concerned.

Whatever无论什么

Whatever,no matter what的区别：

no matter what 只能引导状语从句，而不引导名词性从句。而 whatever 既可引导名词性从句(＝anything that)，也可引导状语从句(＝no matter what)：

1). 引导名词性从句(只用whatever)：

无论他做什么都是对的。

正：Whatever he did was right.

误：No matter what he did was right.

无论他说什么似乎都有道理。

正：Whatever he says sounds reasonable.

误：No matter what he says sounds reasonable.

山羊找到什么就吃什么。

正：Goats eat whatever they find.

误：Goats eat no matter what they find.

2). 引导状语从句(两者可换用)：

无论你说什么，我都不会相信你。

正：Whatever you say，I won’t believe you.

正：No matter what you say，I won’t believe you.

无论发生什么，都要保持镇定。

正：Keep calm，whatever happens.

正：Keep calm，no matter what happens.