1/ Cho đường tròn tâm O, điểm A nằm ngoài đường tròn cách O một khoảng OA=2R (R là bán kính đường tròn), kẻ tiếp tuyến AB của đường tròn ( B là tiếp điểm )

a, Tính số đo các góc của tam giác ABO.

b, Gọi C là điểm đối với B qua OA. Chứng minh: C nằm trong đường tròn

c, Chứng minh: AC là tiếp tuyến của đường tròn.

2/ Cho đường tròn (O;R), từ điểm A nằm ngoài đường tròn vẽ hai tiếp tuyến AB, AC (B và C là các tiếp điểm) H là giao điểm cỏa OA và BC

a, Chứng minh: OA vuông góc BC

b, Chứng minh: OH . OA = \(R^2\)

c, Kẻ đường kính BD. Chứng minh: CD//OA

d, Gọi E là hình chiếu của C trên BD, K là giao điểm của AD và CE. Chứng minh: K là trung điểm của CE

Hãy viết một bài văn về lợi ích khi sống ở thành thị (140 từ)

Cảm ơn Rất Nhiều

1. "Could I help your family?" He said to Mary.

He offered .............................................................................................

2. "I'll definitely get my hair cut this week," Tom said.

Tom promised ......................................................................................

3. "I'm sorry. I can't help you." he said.

He refused ............................................................................................

4. "Oh please! Let me go to Nha Trang with my classmates " she said.

She wanted ...........................................................................................

5. " I'll definitely return by 9 p.m." the man said.

He promised .........................................................................................

6. "I'll tell everyone the news!" He said.

He threatened .......................................................................................

7. "No, I won't go by motorbike," Linda said.

Linda refused ........................................................................................

8. "All right, I'll pick up everyone at 6 p.m tonight."

She agreed ............................................................................................

9. "I will be yours forever ." Daisy says to Peter.

Daisy swears .........................................................................................

10. "Why don't you say out your suggestions?" Mother said to her son.

Mother encouraged ...............................................................................

11. "Don't feed the animals," the guide warned.

The guide warned the tourists ...............................................................

12."Lan, if I were you, I'd go by train." her landlady said........................

The landlady advised ............................................................................

13. "Don't forget to tip the waiter!" she told John.

She reminded .......................................................................................

14. "Please don't break your promise," Mary said to us.

Mary asked us .......................................................................................

15. "If I were you, I'd help these poor children," she said to them.

She advised them ..................................................................................

16. "Don't swim out too far." they say.

She warned her children .......................................................................

17. "Please don't tell my father about it," He said to her.

He begged her .......................................................................................

18. "You can do what you want on Sunday?".Mrs. Brown said.

Mrs. Brown let them ..............................................................................

19. “You should change your way of study.” The teacher said to us .

He advised us ........................................................................................

20. "Take part in our party on Sunday evening, Mary ? "

They had Mary ......................................................................................

21. "Do exactly what I have just told you," I shouted at them.

I made them ..........................................................................................

22. "Would you mind not smoking in my room?" she said to him.

She didn’t let him ................................................................................

23. "Don't be late for class again, Jim."

The teacher asked Jim ...........................................................................

24. "You must fasten your seatbelt."

The stewardess ordered us ...................................................................

25. "You are not allowed to smoke in your room, Dick,'' said his mother:

Dick's mother forbade him ..................................................................

26. "You should not drink too much coffee at night, Olga " said Bob.

Bob advised Olga ..................................................................................

27. "Don't forget to water the flowers for me, Tom."

Mother reminded ..................................................................................

28. “Don’t park your car here .”

He didn’t allow me ................................................................................

29. “Take part in my speaking English Club .”

He encouraged us .................................................................................

30. "No, I didn't cheat in the exam!"

Tom denied ...........................................................................................

31. “Why don’t you go by plane?”

She suggested .......................................................................................

32. “Don’t use this room.”

He doesn’t allow ...................................................................................

33. "Why don't we choose another day?"

Jean suggested ......................................................................................

34. "I lost my temper yesterday."

The teacher admitted .............................................................................

35. “I didn’t hide the knife.”

The boy denied .....................................................................................

36. “You had better tell the truth.”

I advised ...............................................................................................

37. “I hope to see you soon.”

I look forward to ..................................................................................

38. Let me pay for this meal," Ann said.

Am insisted on ......................................................................................

39. "You stole Tim's watch."

Tim's mother accused that boy of ..........................................................

40. "I'm very grateful to you for your help, Mr Smith."

Sue thanked Mr Smith for ....................................................................

41. “I will give you all the information.”

He promises to provide us with ............................................................

42. “Sorry, I couldn't come on Saturday," said David.

David apologized for ............................................................................

43. "Sue ,you passed the exam . Congratulations," said Harry.

Harry congratulated Sue on .................................................................

44. "You scratched my car"

Sophie blamed Thomas for ..................................................................

Biết là dễ nhưng mà lâu cũng ko lên nên em đăng nhờ mọi người giúp đỡ

1. Every morning, Linda (get)………......up at 6. She (have) …………… Breakfast at 6:10. After breakfast, she (brush) …………..her teeth. She (go) ……………..to school at 6:30. She (have) ……………lunch at 11:30 at school.

2. We (watch) …………….T.V every morning.

3. I (do) ……………………my homework every afternoon.

4. Mai and Lan (play) ………………….games after school.

5. Vy (listen) ………………to music every night.

6. Where (be) ………………..your father now?

He (read) ………………..a newspaper.

7. What ………….you (do) ………………? I (be) ……….a student.

8. Where ………….you (go) ……………….now?

I (go) ………………to the market.

9. She is cooking and we (do) ……………………..the housework.

10. He isn't in the room. He (play) ………………..in the garden.

11. Look! The birds (fly) ………………………….

12. I (go) ………………….to school by bus every day, but today I (go) ………………………..to school by bike.

13. Listen! Mai (sing) ………………………….

14. They (play) ………………………volleyball every afternoon. They (play) ……………………volleyball now.

15. Mai (brush) …………………..her teeth every morning. She (brush) ……………………her teeth now.

16. Listen! Lan (play) ……………………….the piano.

17. Mai (be) ………………….tired now.

18. It is 6:00 p.m. Mary is at home. She (have) ………………….. dinner with her family around six o’clock.

19. Where is your father? He is upstair. He (watch) ………………T.V.

He always (watch) ………………………..T.V at night.

20. Our teacher (live) ……………………..on Quang Trung street.

21. Sao and Mai (do) ………………………the housework now.

22. What ………………your mother (do) ……………….?

She is cooking.

23. How …………………you (go) ……………to school every day?

24. Nam (go) ………………..to work by car every day but today he (take) ………………………a bus.

25. Where ………………..your father (work) ……………..?

In the hospital.

26. Look! The teacher (come) ………………………

27. She is very clever. She (speak) ………………….4 languagues.

28. Steve (smoke) ………………….10 cigarettes a day.

29. We usually (have) ……………………dinner at 7:00.

30. Anne (wash) ………………….her hair twice a week.

31. Jane (teach) …………………English to children.

32. You (meet) ………………….a lot of people.

33. He often (go) ………………………….to the cinema.

34. Food (cost) …………………a lot of money.

35. Listen! Somebody (sing) ……………………………

36. She is tired. She (want) ………………….to go home now.

37. How often …………you (read) …………………a newspaper?

38. "Excuse me, but you (sit) ……………………in my place”

"Oh, I am sorry.”

39. "I am sorry" I (not understand) ………………………….. Please speak slowly.

40. What time …............she (finish) ……………work every day?

41. He (not usually drive) ……………………………to work. He usually (walk) …………………

43. Mozart (play) ……………………the piano when he (be) ……………three.

44. Many people prefer (fly) …………………to (go) ………………..by sea.

45. My mother (go) ……………..to the supermarket yesterday evening but she (not buy) …………………….

46 He (move) …………………to Paris in 1917 and (spend) …………… 6 years in Paris.

47. Teenagers like (listen) ……………to the latest pop music.

48. What ……………….you (do) …………..tomorrow morning.

49. Children shouldn't (drink) ……………….coffee. It (not be) ……… Good for their health.

50. My family (watch) …………….T.V every night. But now we (listen) ……………………..to pop music.

51. Yesterday Nga father (start) …………………….his new job.

52. I (meet) …………………..her at the movie theater last night.

53. He (go) ………………….to the English club every Sunday. But last Sunday he (not go) …………………there, he (go) ………………to the City Museum.

54. My mother (make) …………………a dress now.

55. Two years ago, she (teach) ………………at a village school.

56. We (travel) ……………………………to Hue next week.

57. What …………….you (do) …………………yesterday morning.

58. They usually (have) ………………………dinner at home, but they (have) ……………dinner in a small restaurant yesterday evening.

59. The children (be) …………………….here ten minutes ago, but at the moment they (play) …………………….in the jard.

60. Could you (show) ……………………me the way to the bus stop.

61. Lan and Hoa (go) ………………..to the post office now.

62. Liz (need) ……………….some stamps and envelopes.

63. Hoa (mail) ………………….this letter tomorrow.

64. I need (buy) ……………..a phone card.

65. He (phone) …………………….his parents three or four times a week.

66. Nam wants (send) ……………………..this postcard to his penpal.

67. We would like (visit) ……………………Ngoc Son Temple.

68. My hair is dirty. I (wash) ……………….it.

69. We (have) ………………………an English test tomorrow.

70. They usually (paint) ……………………..their house blue.

71. My father (buy) ……………………..a new car 2 months ago.

72. Nam (help) ……………………his father repair the radio at this time.

73. I (be) …………………busy last night, so I (miss) …………….a good film on T.V.

74. Mr Robinson (watch) ……………………..T.V every night.

75. Mrs Mai (make) ………………….all her own clothes. At the moment she (make) …………………..a dress for her daughter.

76. He (teach) ………………….math at this school in 1986.

77. Every body (wait) ……………….for the president in the hall now.

78. You should (go) ……………….to bed early.

79. Lan (be) …………………..very tired when she (catch) …………..a bad cold 2 days ago.

80. She needs (eat) ………………..a lot of vegetables and fruit.

81. I hope you (feel) ……………………..better soon.

82. He (not come) …………………….to the meeting last week.

83. My father never (take) ………………….medicine.

84. There (be) ……………nobody there when I (arrive) …………………yesterday.

85. Yesterday, Hoa and her aunt (go).......................to the supermarket.

86. I would like (tell) ……………you about my family.

87. Vegetables often (have) …………….dirt from the farm on it.

88. Be careful! The children (cross) ………………..the street.

89. I (be) …………….fourteen years old next week, and so will I.

90. My father (not watch) ……………….T.V last night. He (read) ……………..newspapers and magazines.

91. You should (add) ……………a little salt to the spinach when you boil it.

92. When ……………you (buy) ………this dress? Two days ago.

93. I hope you (visit) ……………………….Ha Noi soon.

94. She would like (buy) …………………some bananas.

95. Hoa (receive) ………………….a letter from her mother 2 days ago.

96. It stopped (hurt) ……………….afterwards.

97. I like (watch) ……………………..baseball.

98. The children must (be) …………….back by six o'clock.

99. Marconi (invent) ……….............radio.

100. The disease (spread) ………………..fast now.

101. You ought (finish) ………………………your home work before (watch) ……………..T.V.

102. Hoa (have) ……………….a lot of friends in Hue.

103. Nam and Trung always (visit) ……………their grandparents on Sunday.

104. My father (listen) ……………to the radio everyday.

105. The children (like) ……………….to play in the park.

106. She (not live) …………………….with her parents.

107. Lan (brush) …………………her teeth after meals.

108. The students (not go) ……………………to school on Sunday.

109. Nga (talk) ………………to her friends now.

110. She (be) ……………………...14 on her next birthday.

111. We (visit) ……………………..Huong Pogoda next week.

112. They (live) ……………….with their grandparents.

113. I (come) ………………………back tomorrow.

114. He (have) …………………….a lot of friends.

115. She (have) …………………..a meeting tonight.

116. M y father (jog) ……………………………every morning.

117. We often (play) ……………….tennis in the afternoon.

118. What ……………..you (do) ……………….next Sunday.

119. Phong (watch) …………….T.V everynight.

120. They (go) ……………..to the movies tonight.

121. Tomorrow, She (invite) ………………….all friends to her birthday party.

122. My brother (listen) ……………..to music in his free time.

123. Our friends (come) ……………………here soon.

124. My father never (drink) ………………coffee.

125. I usually (go) ……………….to school by bike but tomorrow I (go) ………………………to school by bus.

126. Jane (play) ………………..the piano at present.

127. He (visit) …………………..his grandparents next week.

128. Jane (play) ……………………..the piano at present.

129. We (not invite) ………………....many friends to the party tonight.

130. Hurry up! we (wait) …………………….for you.

131. Lan and Hoa (read) …………… in the library at the moment.

132. We (not come) ………………………..here tomorrow morning.

133. Listen! The girl (play) ………………….the piano.

134. Nam (go) …………………..to the English club every Saturday.

134. What ……………….you (do) …………….now.

I (grow) …………………some flowers.

135. My father (travel) ………………..to Nha Trang next week.

136. Students often (go) …………………to the school cafeteria at lunch time.

137. You can (find) …………..math books on the racks in the middle.

138. Look! The teacher (come) …………………….here.

139. She (study) …………………..maps in Geography.

140. Ba can (fix) ……………..the lights.

141. They (do) …………………….some experiments at the moment.

142. You (be) …………….a famous author one day.

143. He enjoys (draw) ………………….pictures.

144. Mai (learn) …………………..to play the piano in her free time.

145. I (try) ……………………...to repair the radio now.

146. The students (write) …………………an essay in Literature next Monday.

147. Let us (go) …………………to the English club.

148. I (do) ……………….my math homework at the moment.

149. Next year, my sister (be) ………………..a teacher.

150. When they (be) ……………young, they (leave) …………….their family and (go) ……………………to Ho Chi Minh city.

151. When ………………..Thomas Edison (die) …………………?

In 1931.

Cho hình thang ABCD(AB//CD;AB<CD). Gọi trung điểm của các đường chéo AC, BD theo thứ tự là N và M. Chứng Minh

a,MN//AB

b, MN=\(\dfrac{CD-AB}{2}\)

Cho hình thang cân ABCD(AB//CD) có hai đường chéo AC và BD cắt nhau tại O. Gọi M,N theo thứ tự là trung điểm của BD và AC. Cho biết MD=3MO, đáy lớn CD=5,6cm.

a, TÍnh độ dài đoạn thẳng Mn và đáy nhỏ Ab

b, So sánh độ dài đoạn MN với nửa hiệu các dộ dài của CD và AB