Question

一般现在时怎样变否定句

Answer 1

一般现在时变否定句的规则：
(a)
含有
am
is
are
的句子,变否定句时,只需在am
is
are
后加not.
例：this
is
a
book.
否定句：this
is
not
a
book
.
(b)
含有实义动词的句子,变否定句分两步.
（1）如果主语是第三人称单数时,要在实义动词前加doesn't,后面的动词用原形.
例:he
eats
an
apple.
否定句:he
doesn't
eat
an
apple.
(2)
如果主语不是第三人称单数时,只需在实义动词前加don't.
例:i
teach
english.
否定句
i
don't
teach
english.
(c)
含有情态动词的句子,变否定句时,只需在情态动词后加not.
例:i
can
dance.
否定句
i
can
not
dance.
或
i
can't
dance.
析：当must
be用来表示推测,有“一定”的含义时,否定式要用can
not.
例:you
must
say
something
at
the
mecting.
you
needn’t
say
anything
at
the
mecting.
析：当“must+行为动词”用来表示“必须”的含义时,其否定式可用needn’t
或mustn't表示“不需要”,“不必”,语气委婉,must
not表示“禁止”,“千万别”语气生硬.
例：you
may
come
in
now.
you
mustn't
come
in
now.
析：may作为情态动词表示“可以”时,其否定式用must
not,而不用may
not.
例：
he
may
watch
tv
.
he
mustn't
watch
tv.
注意:
(1)
见到some
变否定句时,要换成any.
例：
i
eat
some
apples.
否定句
i
don't
eat
any
apples.
(2)
见到and
变否定句时,要换成or.
例：there
is
some
air
and
water
on
the
moon.
否定句
there
isn't
any
air
or
water
on
the
moon.
(3)
见到too和also变否定句时,要换成either.
例:tom
goes
to
school
too.
否定句
tom
doesn’t
go
to
school
either.
too和also用于肯定句中时,否定句中用either替换.
（4
)见到already变否定句时,要换成yet.
例:he
has
had
supper
already.
he
hasn’t
had
supper
yet.
随着对谓语动词的否定,某些副词也要作相应的变动.

Answer 2

一般现在时变否定句的规则.
(a)
含有
am
is
are
的句子,变否定句时,
只需在am
is
are
后加not.
例1
This
is
a
book.
否定句
This
is
not
a
book
.
例2
I
am
a
teacher
.
否定句I
am
not
a
teacher
.
例3
These
are
pens
.
否定句These
are
not
pens
.
(b)
含有实义动词的句子，变否定句分两步。
（1）如果主语是第三人称单数时，要在实义动词前加doesn't,后面的动词用原形。
例1
He
eats
an
apple.
否定句
He
doesn't
eat
an
apple.
例2
Jim
does
his
homework.
否定句
Jim
doesn't
do
his
homework.
例3
Marry
goes
to
school.
否定句Marry
doesn't
go
to
school.
(2)
如果主语不是第三人称单数时，只
需在实义动词前加don't.
例1
I
teach
English.
否定句
I
don't
teach
English.
例2
They
go
to
school.
否定句
They
don't
go
to
school.
例3
We
sing
a
song.
否定句
We
don't
sing
a
song.
(c)
含有情态动词的句子,变否定句时,
只需在情态动词后加not.
例1
I
can
dance.
否定句
I
can
not
dance.
或
I
can't
dance.
例2
They
can
speak
English.
否定句
They
can
not
speak
English.
或
They
can't
speak
English.
例3
He
must
go
home.
否定句
He
must
not
go
home.
或
He
mustn't
go
home.
例4
He
must
be
on
the
playground.
He
can
not
be
on
the
playground.
析：当must
be用来表示推测，有“一定”的含义时，
否定式要用can
not.
例5
You
must
say
something
at
the
mecting.
You
needn’t
say
anything
at
the
mecting.
析：当“must+行为动词”用来表示“必须”的含义时，
其否定式可用needn’t
或mustn't表示“不需要”，“不必”，
语气委婉，must
not表示“禁止”，“千万别”语气生硬。
例6
You
may
come
in
now.
You
mustn't
come
in
now.
析：may作为情态动词表示“可以”时，
其否定式用must
not,而不用may
not.
例7
He
may
watch
TV
.
He
mustn't
watch
TV.
注意:
(1)
见到some
变否定句时,要换成any.
例1
I
eat
some
apples.
否定句
I
don't
eat
any
apples.
例2
He
has
some
books.
否定句
He
doesn't
have
any
books.
例3
He
does
his
home
work.
否定句
He
doesn't
do
his
home
work.
(2)
见到and
变否定句时,要换成or.
例1
There
is
some
air
and
water
on
the
moon.
否定句
There
isn't
any
air
or
water
on
the
moon.
例2
He
has
some
brothers
and
sisters.
否定句
He
hasn't
any
brothers
or
sisters.
例3
He
eats
apples
and
oranges.
否定句He
doesn’t
eat
apples
or
oranges.
(3)
见到too和also变否定句时,要换成either.
例1Tom
goes
to
school
too.
否定句
Tom
doesn’t
go
to
school
either.
too和also用于肯定句中时，否定句中用either替换。
（4
见到already变否定句时,要换成yet。
例1
He
has
had
supper
already.
He
hasn’t
had
supper
yet.
随着对谓语动词的否定，某些副词也要作相应的变动。

Answer 3

一般在系动词或助动词后加NOT，例如：
She
is
six.而否定是She
is
not
six.
其中IS为系动词