Which one is correct?
The Moon has been sighted.
The Moon is being sighted.
You would not usually need to use ‘is being’ in that context, so probably the first. However the tenses are both possible so without additional context it’s impossible to say for certain whether either of those are correct - or whether a different tense altogether would be more appropriate.
Thanks Beeesneees 
I have used the sentence in the sense that we were sighting the moon and then we sighted it.
I think for my sentence, “The moon is sighted” would be correct.
You can guide me better if you have got my point.
Thanks
It sounds as if you just need the simple past tense:
We saw the moon. / The moon was seen.
We sighted the moon. / The moon was sighted.
Thanks
Correct these also please
This (idea) is new to me.
or
This (idea) is new for me.
She exercises
or
She takes exercise
Which are correct?
Why have your written ‘idea’ in brackets?
‘This idea is new to me,’ is probably the usual form, though ‘for me’ is possible too.
Both ‘she exercises’ and ‘she takes exercise’ are correct.
Ok, thanks
I wrote idea in brackets because instead idea I could write thing/ proposal anything.
I have another question, please tell me
I am a student, am I not?
I am a student, aren’t I?
Which one is correct and why?
‘Am I not?’ complies with the traditional pattern but sounds very formal and would usually be used for dramatic effect only. ‘Aren’t I?’ is more acceptable.
Thank you so much Sir.
Here are couple of other questions.
Which one is correct?
How do I dare disobey you?
Or
How do I dare to disobey you?
Which of the favours of your God you will deny?
Or
Which of the favours of you God will you deny?
Another please, correct it also
Is this sentence right?
Having come there, you would feel good.
Is it same if I write?
You will feel better on coming here.
How do I dare disobey you / to disobey you are both possible, but I suspect that what you are trying to say would be better expressed as:
How would I dare (to) disobey you?
or possibly even just
Would I dare (to) disobey you?
‘… your God’ would be correct, but I don’t find the second sentence particularly natural sounding, so again I wonder if it would be used in the situation which you are imagining or if there would be a better (more natural sounding) alternative.
This doesn’t seem to make much sense, when using ‘come’ and ‘there’ together. Also you then seem to have substituted ‘here’ for ‘there’ in the alternative. Could you explain a little more please?
So sorry Beeesneees, I made a mistake in the last sentence. I wanted to write
You will feel better on coming there.
Is it correct?
Ok, you mean “Having come there, you would feel good” is not right. Right?
Thanks for the correction of the above sentence. Actually I wanted to ask the position of “will”
Which of the favours of your God you will deny?
Or
Which of the favours of your God will you deny?
Which position of"will" is correct?
I read that double negatives are not allowed in English sentences. Is it same for double questioning also? As in me second sentence there are double questioning.
Please tell me in this context which sentence is right?
“Having been there, you would feel good”
“If you come there, you will feel good.”
Which of the favours of your God will you deny?