Chia động từ trong ngoặc

1. Mary (be)... Lan's pen pal
2. She (enjoy)... the peaceful atmosphere while Mary was praying
3. I hope we (keep)... in touch
4. .....he (write)... his report yet?
5. It's dangerous...... in the river (swim).
6. Many teenagers enjoy (use)... social media like Facebook or Zalo