第二个句子是错误的。
i
don't
know
how
to
do
it的话就是正确的。
前面个句子的what是疑问//www.souquanme.com代词，可以充当know的宾语，因此后面不要搜趣网it
后面的搜趣网话how是疑问副词，不能充当宾语，所以后面还要一个it。
满意的话别忘了采纳哦~
谢谢。

Are you joking? 你在开玩笑吗?What are you doing? 你在做什么?How are you going?你现在怎么样?Are you making your homework? 你在做作业吗Where are you living?你现在住哪?When will you eating di//www.souquanme.comnner? 你什么时候吃饭(指就近的)

1.
Could
you
tell
me
how
to
get
to
the
park?
2.
We
don't
konw
where
to
go.
3.
He
didn't
know
when
to
meet
his
unlce.
4.
What
to
do
next
is
a
problem.
5.
Do
you
know
how
to
repair
this
computer?