Choose the correct verb.

Dear Andrew,

Thanks a lot for your email. I ... glad to hear from you again.
I ... be happy to answer your questions. As for me, the most difficult in learning English ... usage verb tenses correctly. To improve grammar knowledge I ... extra classes in my school. Also, the best way to learn a foreign language is listening to audios or watching videos and films.

Sorry, I have to go now, I ... a lot of homework to do.
Write back soon.

Best wishes,
Dima