The sentence is gramatically correct but I would recommend you to use something like this.
Attached herewith is my resume and biodata.
or
Please find my attached resume for your perusal.
Yes, but it sounds a bit awkward. First, you would use "hereto" not "herewith," but that sounds quite formal. I would say "I have attached my resume and biographical data to this letter/email/fax/etc" or "Please find attached my resume and biographical data."
"That was wrong" is a grammatically correct sentence.
This sentence is not grammatically correct. For the sentence to be grammatically correct, the space between "in" and "to" would have to be removed. Therefore the sentence should read "They are into skating."
The sentence is grammatically correct.
'What a drunkard you are' is a grammatically correct English sentence.
Yes, it is grammatically correct.
'Rhoda's crazy' is grammatically correct.
That sentence is grammatically correct.
This sentence is grammatically correct.
This sentence is grammatically correct.
No it should be "You were not there"...
This sentence is grammatically correct.