Question

正确的句子是I don't know what I should say还是I don't know what should I say.

求解释在宾语从句里什么时候可以直接在what等代词后面跟疑问词，比如can do will等等；什么时候疑问词要放在主语后面？

Answer 1

I
don't
know
what
I
should
say
=
I
don't
know
what
to
say
以下是有关宾语从句的一些内容，希望对您有所帮助。
一.宾语从句的定义
置于动词、介词等词性后面起宾语作用的从句叫宾语从句。宾语从句的语序必须是陈述语序。谓语动词、介词、动词不定式，v.-ing形式后面都能带宾语从句。有些形容词（afraid,sure,glad等）之后也可以带宾语从句。
二.宾语从句中引导词的用法在复合句中作主句的宾语，引导词有：
连词：that
(that
常可省略),whether,
if
代词：who,
whose,
what
,which
副词：when
,where,
how,
why
等。
（一）that引导的宾语从句（在非正式场合that可以省略）
可跟that从句做宾语的动词有：
say,
think,
insist,
wish,
hope,
demand,
imagine,
wonder,
know,
suppose,
see,
believe,
agree,
admit,
deny,
expect,
explain,
order,
command,
feel,
dream,
suggest,
hear,
mean,
notice,
prefer,
request,
require,
propose,
declare,
report等。
例句：The
boy
believes
that
he
will
travel
through
space
to
other
planets.
注意事项：当主句谓语动词是
think,
believe,
suppose,
expect
等词，而宾语从句的意思是否定时，常把否定转移至主句表示。
例句：I
don’t
think
it
is
right
for
him
to
treat
you
like
that.
在以下情况中that不能省略
1.当句中的动词后接多于两个由that引导的宾语从句时，第一个that可省，但后面的that不可省。
例句：He
said
(that)
you
were
too
young
to
understand
the
matter
and
that
he
was
asked
not
to
tell
you.
2.当主句的谓语动词与that宾语从句之间有插入语时，that一般不可省。
例句：Just
then
I
noticed,
for
the
first
time,
that
our
master
was
wearing
his
fine
green
coat
and
his
black
silk
cap.
3.当that从句是双宾语中的直接宾语时，that不可省。
例句：I
can’t
tell
him
that
his
mother
died.
注意事项：许多带复合宾语的句子，that引导的宾语从句经常移到句子后部，而用it作形式宾语。
例句：I
find
it
necessary
that
we
should
do
the
homework
on
time.
（二）由whether,if
引导的宾语从句
由whether(if)引导的宾语从句，实际上是一般疑问句演变而来的。意思是“是否”。宾语从句要用陈述句语序。一般说来，在宾语从句中whether与if可以互换使用，但在特殊情况下if与whether是不能互换的。
例句：I
wonder
whether(if)
they
will
come
to
our
party.
只能用whether，不能用if引导的宾语从句
1.在带to的不定式前
例句：We
decided
whether
to
walk
there.
2.在介词的后面
例句：I’m
thinking
of
whether
we
should
go
to
see
the
film.
3.在动词后面的宾语从句时
例句：We
discussed
whether
we
had
a
sports
meeting
next
week
4.直接与or
not连用时
例句：I
can’t
say
whether
or
not
thet
can
come
on
time.
只能用if不能用whether引导的宾语从句
1.if引导条件状语从句，意为“如果”
例句：The
students
will
go
on
a
picnic
if
it
is
sunny.
2.if引导否定概念的宾语从句时
例句：He
asked
if
I
didn’t
come
to
school
yesterday.
3.引导状语从句even
if（即使）和as
if（好象）时
例句：He
talks
as
if
he
has
known
all
about
it.
（三）连接代词和连接副词引导的宾语从句
这样的宾语从句实际上是由特殊疑问句变化而来的，宾语从句要用陈述句语序。用于这种结构的动词常常是：see,
say,
tell,
ask,
answer,
know,
decide,
show,
find
out,
imagine,
suggest,
doubt,
wonder,
discover,
understand,
inform,
advise等。
英语中的连接代词有：who,whom,whose,which,what,在句中担任主语、宾语、定语或者表语。
例句：Can
you
tell
me
whom
you
are
waiting
for?
英语中的连接副词有：when,where,why,how，在句中担任状语的成分。
例句：None
of
us
knows
where
these
new
parts
can
be
bought.
三.宾语从句的语序宾语从句的语序是陈述句语序即：连接代词/副词+主语+谓语+其他成分。例句如下：
1.I
don’t
know
what
they
are
looking
for.
2.Could
you
tell
me
when
the
train
will
leave?
3.Can
you
imagine
what
kind
of
man
he
is?
四.宾语从句的时态1.主句是一般现在时，从句根据实际情况使用任何时态。
例句：The
headmaster
hopes
everything
goes
well.
2.主句是过去时态，从句须用过去时态的某种形式。
例句：She
was
sorry
that
she
hadn’t
finished
her
work
on
time.
3.当宾语从句表示的是一个客观真理或者事实时，即使主句是过去时，从句也用一般现在时态。
例句：The
teacher
told
his
class
that
light
travels
faster
than
sound.
五.宾语从句的特点1.宾语从句可以作及物动词、介词及形容词的宾语。
2.宾语从句的语序一律用陈述句语序。
3.连接词that引导宾语从句在句中无词义，不充当句子成份，多数情况下可以省略。
4.whether
和
if
都可引导宾语从句，但
whether后可紧跟or
not；whether从句可作介词的宾语。
5.如果从句太长，可以用形式宾语it.