BBC ESL-Definite articles

Last clss, I really don't know about articles. I know what 'articles' means, but I can't use right articles in sentences. So I entered BBC ESL and studied. The paragraph is..

The country I'd most like to visit is India. I'd to take a train ride
only one thing                                                       first time to tell
down the western coast and a boat trip along the Yamuna River. Of
    only one thing        first time to tell         before special noun
course, I'd visit the Taj-Mahal, it's probably the most famous
                                                                     superatives
building in the whole country. I'd like to go there with my family.
                only one thing
My partner and I have 3 children-2 girls and a boy and I'd love the
                                                    first time to tell     refer second time
children to see and experience India while they're still young.

I answered all right articles! I'm very happy. It's useful to me.