Question

英语填空！看补充！

When wine was first made, wine makers found that it turned sour(酸的) instead of staying sweet. They did not know what to do. 为什么这句"They did not know what to do"要用what to do而不用how to do？可以讲下what to do和how to do的用法吗？谢谢

Answer 1

what
to
do是正确的。但是how
to
do是不对的，必须在do后面加上宾语。
1.
what
to
do和how
to
do
it在英语中被称为“疑问词
+
不定式”结构。
该结构在功能上相当于一个名词短语,在句中一般充当名词所能做的成分,比如主语/宾语/表语等.请看以下例子:
I
don't
know
what
to
do.
what
to
do做know的宾语
When
to
hold
the
meeting
hasn't
been
decided.
When
to
hold
the
meeting做句子的主语
The
problem
is
how
to
do
it.
how
to
do
it做句子的表语
2.
该结构可以细分为两种:
1)
疑问代词+不定式
特点:疑问代词要充当不定式中的介词或动词的宾语
如:
what
to
do中what充当do的宾语,即"做什么"
再如:
I
don't
know
whom
to
send
this
gift
to.
whom充当第二个to(介词)的宾语,即to
send
this
gift
to
whom,"把礼物送给谁"
2)
疑问副词+不定式
特点:疑问副词要充当不定式所表示动作的状语
如:
I
don't
know
how
to
do
it.
how充当do
it的方式状语
3.
如果能掌握上述结构的真正含义,
相信大家都能明白:
what
to
do
√
而what
to
do
it
×
how
to
do
it
√
而how
to
do
×
4.
另附两个特殊用法
1)
该结构经常可以换成名词性从句来表达
如:I
don't
know
what
to
do.=I
don't
know
what
I
should
do.
I
don't
know
how
to
do
it.=I
don't
know
how
I
can
do
it.
2)
表达"是否该做某事"
只能用whether
to
do
sth而不能用if
to
do
sth
如:
I
don't
know
whether
to
finish
my
work
first