I. Choose the words whose underlined part is pronounced differently from that of the others in each group.(chọn từ phát âm khác với từ còn lại) 21. A. this B. think C. thank D. thieves 22. A. gather B. bathe C. birthday D. weather 23. A. tooth B. breathe C. through D. earth 24. A. thirty B. than C. therefore D. those 25. A. mouth B. Thursday C. nothing D. worthy 26. A. both B. teeth C. smooth D. fourth 27. A. weather B. wealthy C. clothing D. bathing 28. A. though B. thank C. throw D. thin 29. A. southern B. neither C. thus D. third 30. A. author B. those C. width D. think 31. A. thin B. than C. they D. there 32. A. birthday B. earth C. worth D. there 33. A. another B. death C. brother D. though 34. A. thank B. mother C. thunder D. throat 35. A. they B. three C. thirst D. thread 36. A. worth B. thick C. though D. wrath 37. A. Thursday B. than C. there D. those 38. A. Thursday B. thanks C. these D. birthday 39. A. thought B. without C. theater D. tooth 40. A. weather B. wealthy C. clothing D. bathing 41. A. thirsty B. both C. Thanksgiving D. there 42. A. weather B. through C. warmth D. tooth 43. A. than B. their C. earth D. then 44. A. birthday B. although C. thing D. theatre 45. A. anything B. neither C. than D. feather 46. A. think B. thought C. theatre D. there 47. A. mother B. through C. leather D. either 48. A. them B. they C. something D. this 49. A. thirty B. though C. fifth D. thanks 50. A. everything B. brother C. theory D. both