1. Rewrite the following sentence without changing its meaning. Use the given word(s) if any. 16. "Where are you going to stay when you visit the Red Dao village?" she asked me. → She asked me_ 17. Viet Nam has 54 ethnic groups. - (THERE). 18. We were running in the park. A strange object suddenly appeared there. - -> When While_ 19. "She can't live without her cats.", Mandy said. Mandy said that. 20. "How does he go to the postoffice?" → She asked him. 2. "These days, many teenagers spend too much time on social network (Zalo, Facebook, Tik Tok...." Cues: What are its effects to teenagers' study / health......? What are the solutions for this problem?