Question

Please check my answer thanks :)

In the sentence "Although the book was more than 50 years old, it still contained helpful information", the word although is what.

I said it's adjective

Answer 1

It's a subordinating conjunction:
http://grammar.ccc.commnet.edu/grammar/conjunctions.htm
(Scroll down to Subordinating Conjunctions.)

=)

Answer 2

thanks i understand now :)

Answer 3

You're welcome.

=)

Answer 4

In the sentence "Although the book was more than 50 years old, it still contained helpful information," the word Although is a(n)