1. I've worked her for/since 6 years. 2. He has lived in Berlin for/since three months.
3. Florencia has studied English for/since she was 7 years old.
4. We've been waiting for/since 12 hours. 5. They have been practicing for/since months.
6. Augusto has known Malvina for/since 2011.
1)for 2)for 3)since 4)for 5)since 6)for