以下是50个有关肯定句和否定句的英文句子：

肯定句：

1. The sun rises in the east.

2. I am a student.

3. He is a doctor.

4. It is a beautiful day.

5. They are happy.

6. She is a teacher.

7. The dog barks loudly.

8. I like cats.

9. The book is on the table.

10. He is taller than me.

11. We are friends.

12. She has a cat.

13. The sun is hot.

14. I have a phone.

15. He is strong.

16. The car is fast.

17. She is smart.

18. I eat breakfast every day.

19. The boy is playing soccer.

20. The teacher is nice.

21. The phone is working.

22. She is beautiful.

23. The computer is useful.

24. I have a headache.

25. The dog runs fast.

26. She is a good student.

27. The teacher is funny.

28. I buy coffee every morning.

29. He is a good friend.

30. The sun is shining.

31. She is a successful woman.

32. I have a lot of work to do.

33. The car is comfortable.

34. She is a hardworking person.

35. I am interested in learning.

36. The book is interesting.

37. He is a talented artist.

38. I have a good day.

39. The sun is warm.

40. She is a caring person.

41. I am happy to be alive.

42. The water is blue.

43. She is a valuable member of our team.

44. I have a lot of friends.

45. The food is delicious.

46. He is a reliable person.

47. I am a happy customer.

48. The service is excellent.

49. She is a great mother.

50. The weather is nice.

否定句：

1. The sun does not rise in the east.

2. I am not a student.

3. He is not a doctor.

4. It is not a beautiful day.

5. They are not happy.

6. She is not a teacher.

7. The dog does not bark loudly.

8. I do not like cats.

9. The book is not on the table.

10. He is not taller than me.

11. We are not friends.

12. She does not have a cat.

13. The sun is not hot.

14. I do not have a phone.

15. He is not strong.

16. The car is not fast.

17. She is not smart.

18. I do not eat breakfast every day.

19. The boy is not playing soccer.

20. The teacher is not nice.

21. The phone is not working.

22. She is not beautiful.

23. The computer is not useful.

24. I do not have a headache.

25. The dog runs not fast.

26. She is not a good student.

27. The teacher is not funny.

28. I do not buy coffee every morning.

29. He is not a good friend.

30. The sun is not shining.