either/neither/too/so

Here are the correct answers with the specified adverbs (either, neither, too, or so) added to each sentence: 1. I really miss Kate. (Neither 'either', 'neither', 'too', nor 'so' is necessary here.) 2. I was so tired after the game. (This sentence already has 'so', so no change is needed.) 3. I haven't tried Chinese food before. I haven't either. (Correct - 'either' is used correctly here.) 4. We reunite with my high school friends once a year. We do too. (Correct - 'too' is used correctly here.) 5. I don't want to lose my job. Neither do I. (Correct - 'neither' is used correctly here.) 6. I have never witnessed anything like this before. Neither has my sister. (Correct - 'neither' is used correctly here.) 7. My cousins went to the movie theater yesterday. So did my uncle. (Correct - 'so' is used correctly here.) 8. I couldn't talk to the director yesterday. My colleague couldn't either. (Correct - 'either' is used correctly here.) 9. I got an 'A' in English class. So did I. (Correct - 'so' is used correctly here.) 10. I am not going to work tomorrow. Neither am I. (Correct - 'neither' is used correctly here.) 11. Your sister can't help you with your homework. I can't either. (Correct - 'either' is used correctly here.) 12. My father is so proud of you, is my mother. (This sentence doesn't fit grammatically with any of the options; a better option would be 'My father is so proud of you, and my mother is too.') 13. My parents didn't believe in you. I never did either. (Correct - 'either' is used correctly here.) 14. I haven't received any warnings yet. Neither has my brother. (Correct - 'neither' is used correctly here.) 15. They bought a new house. So did I. (Correct - 'so' is used correctly here.) 16. We won't cancel our plans for you. Neither will they. (Correct - 'neither' is used correctly here.) 17. Nobody was there. I wasn't there either. (Correct - 'either' is used correctly here.) 18. Everybody is leaving in 10 minutes. So am I. (Correct - 'so' is used correctly here.) 19. You are late. So am I. (Correct - 'so' is used correctly here.) 20. They wouldn't understand me, would you. (This sentence is a bit awkward; a better option would be 'They wouldn't understand me, nor would you.')