Одно обстоятельство требует уточнения. Use "I", " you", "he", " she", "am", " it", "we" or "they" 1. ... is a doctor,and ... am a vet. 2. This is out house. ... is very nice and comfortable. 3. What's this? ... is my cat, ... is not very friendly.  4. How are ...? - ...'m fine,thanks. And ...? 5. Meet Tom and Betty, ... are my best friends. 6. ... am a first year student. ... am very happy. 7. My sistet is a teacher. ... is thirty years old.  8. ... are a very happy family.

1.HE is a doctor,and I am a vet. 

 2. This is out house.
IT. is very nice and comfortable.

3. What's this? IT is my cat, IT is not very friendly.

 4. How are YOU? -I'm fine,thanks. And YOU?

 5. Meet Tom and Betty, THEY are my best friends.

 6. I am a first year student.I am very happy.

 7. My sistet is a teacher. SHE is thirty years old.

8. THEY are a very happy family.