一。将肯定句变为否定句时,一般情况下在句中助动词。系动词或情态动词后加not。但有时并非如此,而是要改变句中的某些词。现列举如下:

　　(一)改变副词。例如:

　　1.He is always late for school.→

　　　He is never late for school.

　　2.The boy almost always goes to bed at 10 o'clock.→

　　　The boy hardly ever goes to bed at 10 o'clock.

　　3.He is still a worker.→

　　　He is no longer a worker.

　　(二)改变连词。例如:

　　Both Jim and Tom like reading.→

　　Neither Jim nor Tom likes reading.

　　(三)改变不定代词。例如:

　　All of the students are from the countryside.→

　　None of the students are from the countryside.

　　(四)改变限定词。例如:

　　1.He spent much time playing every day.→

　　　He spent little time playing every day.

　　2.Many people know the news.→

　　　Few people know the news.

　　二。肯定句变否定句时,既可以在句中助动词。系动词或情态动词后加not,也可以不加not,而只须改变句中的某些词。例如:

　　1. He knows everything about your school.→

　　He doesn't know anything about your school.

　　He knows nothing about your school.

　　2. I know both of them.→

　　　 I don't know either of them.

　　　I know neither of them.

　　3.Tom feels happy today.→

　　　Tom doesn't feel happy today.

　　　Tom feels unhappy today.

　　4.The boy looks like his father.→

　　　 The boy doesn't look like his father.

　　　The boy looks unlike his father.

　　三。变否定句时,某些形容词。不定代词。副词等也随之改变。例如:

　　1. I can see some mountains far away.→

　　　 I can't see any mountains far away.

　　2.He has already had breakfast.→

　　　 He hasn't had breakfast yet.

　　3.We can swim, too.→

　　　We can't swim, either.

　　4.Jim likes meat a little.→

　　　Jim doesn't like meat at all.

　　四。当主句谓语动词是think, suppose, believe, guess和imagine等时,后面的宾语从句要表示否定意义时,通常将not提到主句的位置上。例如:

　　I think his proposal is valuable.→

　　I don't think his proposal is valuable.

　　注:not和代词all, each, everyone, everybody及副词both, quite, altogether, always等连用时表示部分否定。例如:

　　1.Not all the students prefer maths.并非所有的学生都喜欢数学。

　　2.It is not always sunny here.这里并不总是阳光普照。

　　3.The answer is not quite proper.这个答案不完全正确。

　　(文/迟本文高吉鹏；英语辅导报初三版03--04学年度第29期；版权归英语辅导报社所有，独家网络合作伙伴新浪教育，未经许可，不得以任何形式进行转载。)