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。
