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41. I haven't seen Nam for 3 years.
42. Carol told Peter not to make so much noise.
43. It's very important to keep the environment clean.
44. Mrs.Hoa suggested turning off the lights before going out.
45. Let's plant some trees around your house to get more fresh air.
46. My brother will buy a new computer if he has enough money.
47. Nam does not speak English as fluently as friends.
48. Liz has not sent us a letter since she returned to the USA.
49. Tet is an important festival which occurs in late January or early or early February.
50. A lot of trees will be planted along the streets by students of Ngo Sy Lien High School.

câu 41. I haven't seen Nam for 3 years.
câu 42. Carol told Peter not to make so much noise.
câu 43. It's very important to keep the environment clean.
câu 44. Mrs.Hoa suggested turning off the lights before going out.
câu 45. Let's plant some trees around your house to get more fresh air.
câu 46. My brother will buy a new computer if he has enough money.
câu 47. Nam does not speak English as fluently as friends.
câu 48. Liz has not sent us a letter since she returned to the USA.
câu 49. Tet is an important festival which occurs in late January or early February.
câu 50. A lot of trees will be planted along the streets by students of Ngo Sy Lien High School. 

 (mik ko copy nha)