Giup ko bt lm xin cảm ơn

1: They can't talk with words but they can talk with sounds

(Sentence 1+2 P1)

2. School of Dolphins is a group of dolphins (Sentence 1+2 P2)

3. They talk to other dolphins in the school (sentence 1 P3)

4. They say "welcome" when dolphin comes back to the school (sentence 3 P3)

5. Under water 

6. No. Because the sounds are very,very high

7. They are sad and lonely

8. Many people believe that dolphins bring good luck