"I don't know" vs "I have no idea"

[Edison_Chen_e_c]

<Question1> analysis
I don't know what the truth is.
S:I
V:know
O:what the truth is

I have no idea what the truth is.
S: ?
V: ?
O: ?

<Question2> Which one(s) is/are correct?
I have no idea about it.
I have no idea it.
I have no idea what the truth is.
I have no idea about what the truth is.

Thanks.

[Lost_Soul]

We're not doing your homework for you,
Please, post your ideas first :)

[Edison_Chen_e_c]

Ohh, it's not my homework, I'm not that kind of a kid, who doesn't want to do the work. :wink: What I ask are the things I haven't understood clearly in school. I'm not that kind of teen really. :wink:

My thought is that: I can easily point out that 'I' is the subject, 'know' is the verb, and 'what to do' is the object of the verb 'know'.
"I don't know what to do."

Yet I don't understand where the object is, and what is the object of.
"I have no idea what to do."

I know the subject is 'I'
the verb is 'have'
the object is 'idea'
then what about 'what to do' what is it??

[Mister Micawber]

'.
I - S
have - v
no idea - O
what to do - Object complement
.
_________________
Native English teacher at Mister Micawber's

[Edison_Chen_e_c]

One more, need prep 'about'?

Which one(s) is/are correct?
I have no idea about it.
I have no idea it.
I have no idea what the truth is.
I have no idea about what the truth is.

[Mister Micawber]

.
These are OK:

I have no idea about it.
I have no idea what the truth is.
I have no idea about what the truth is.
.
_________________
Native English teacher at Mister Micawber's

[Edison_Chen_e_c]