Ответ:

4. Yes I tried, but it is very hard, without teachers explanation

5. I think the most effective way is, teach with teacher.

8. because I want visit some new places in the future. Yes, I think  it is hard, but i can do it.

9. They will be able to visit other countries and speak with foreigners.

10. Nowadays, it is becoming more popular. People want to learn languages, because this is the path to success.