His.
His is a possessive pronoun and Katie's is possessive so you should use his
No, it is not grammatically correct to say "what a fun." It should be corrected to "What fun!" to make it grammatically accurate.
This is not acceptable in English English but it may be in American. (Americans say: meet with you. In England we say: meet you.)
It is not, but it is widely used because it conveys the general idea of the question as well as its grammatically correct version.No you should say "Where are you" the at at the end is not needed.
this one --> these ones (or merely these). seems fine to me.
It should be: Yes, it is impossible. but, yes.
Different 'from' is grammatically correct.Different 'from' is correct.
It is almost grammatically correct but not quite.You should say: Both of you have the same hats.You could also say: You both have the same hats.
I would have to say no. I believe it would be "Do you have a pen" or "Do you have any pens".
What is grammatically correct is "in the space provided" not "on the space provide" and yes, delete "for"
It is grammatically correct to say: There is nothing wrong with this machine.It is not grammatically correct to say: Will it is be grammatically correct to say ....The correct way to write that or say that would be: Would it be grammatically correct to say....
No, it is not correct grammatically. The correct phrasing would be "Should I take these?" or "Should I take these ones?"
The latter form is grammatically correct but the former is in popular usage.