英语陷阱(4)

 
英语陷阱(4)

I couldn't have got to Slough in time unless I'd had a helicopter.
除非我有一架直升�w�C, 否�t我是不可能在那���r候�s到S地的.
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 一般的英�Z�Z法��和�o典都����到, �B接�~unless的涵�x和if...not相同,
它��可以互�Q使用. 例如: I  shan't go unless he asks me.
等于I shan't go if he does not ask me. (Eckersley's A comprehensive English Grammar);
 You will fail unless you work harder. 等于You will fail if you do not work harder.
(A.S. Hornby's The Advanced Learner's Dictionary of Current English).
其��, �@�拥奶岱ㄊ遣��蛉�面的, 因�榇嬖谥��@么一�����}: unless和 if...not
是否在各�N�龊舷露寄芑��Q使用呢? �F以上例--I couldn't have got to Slough
in time unless I'd had a helicopter. �槔��硖接�一下�@�����}.

 此句引自��外�罂�. �f��人被控犯了�\�⒆�, 在法庭他自�q�f:"�l生此案�r,
我并不在S地, 而是在�xS地几十里外的另一��小��上, �P于�@�c我可以提供人�^......".
接著他�f道:"I couldn't have got to Slough in time unless I'd had a helicopter."
如果遵照一般�Z法��所述的公式: unless=if...not, �⒋司涓淖�I couldn't have got to
Slough in time if I'd not had a helicopter, 那���a生怎�拥暮蠊�呢? 若改作if...not,
其涵�x是: I did have a helicopter and I did get to Slough in time to commit the murder.
 �@而易��, �@并不是衽所想�f的��. ��此, unless是在大多���龊舷驴膳cif...not互�Q使用,
但在某些�龊侠�(例如在某些�^�Z�釉~用���M�Z�獾木渥永�)�s不能相互置�Q,否�t它�����a生截然相反的涵�x.

 值得注意的是, unless用在���M�Z�饩渲��r, 存在著�煞N可能性. 在某些句子中,
它表示if...not的涵�x, 可以和if...not互�Q使用. 例如:
   Unless you had lent me a hand, I should not have fulfilled my task.
   = If you had not lent me a hand, I should not have fulfilled my task.
   要不是你�����兔�, 我是不可能完成任�盏�.

 然而, 在另一些�龊侠�, unless并不是表示 if...not的涵�x, 而是表示近似于but...if的涵�x.
 �@�r候, 可以改����but...if, 但�Q不能用if...not去替代. 例如, 衽在法庭上所�f的那一句, 可以改����:
   I could not have got to Slough, but I could have got to Slough if I had had a helicopter.

 ��有一�c����注意的是, unless句型和if...not句型具有�]的倏色彩和表�_�L格,
前者是�e�O的�f法, �B度明朗, �Z�庥辛�; 后者是退一步的�f法, �B度含糊, �Z�廛�弱�o力.
 
 �F在, 你能否�f出下列����句子的不同涵�x?
 I should not expect their help unless they were my friends.
 I Should not expect their help if they were not my friends.