Question

Meghana gave me a book .It was very interesting (combine with that)

Answer 1

Hi 
Thank you for the question
If you want to connect the two sentences with that then the punctuation will be removed because the sentence will continue so the sentence becomes as follows 
" Megan gave me a book that was very interesting "
Hope the answer helps you
Mark it as brainliest if it did
Thank you

Answer 2

Thank for asking this type of interesting question as it tells how much interest you have in study.
This is very simple and easy question just put the word "that" in center and removed the punctuation that will make the sentence like that.

"Maghana gave me a book that was very interesting"
i am hoping this will help you in understanding the further questions like that
and in your further study.