Một chiếc kệ sách để bàn gồm các giá đỡ là 9 hình tam giác đều bằng nhau. Biết cạnh tam giác đều là 18cm và khoảng cách giữa mỗi tam giác đều là 2cm. Biết giá một mét nguyên liệu là 50 000 đồng. Em hãy tính tiền nguyên liệu phải trả khi thiết kế chiếc giá đỡ trên

Một chiếc kệ sách để bàn gồm các giá đỡ là 9 hình tam giác đều bằng nhau. Biết cạnh tam giác đều là 18cm và khoảng cách giữa mỗi tam giác đều là 2cm. Biết giá một mét nguyên liệu là 50 000 đồng. Em hãy tính tiền nguyên liệu phải trả khi thiết kế chiếc giá đỡ trên

tính chiều rộng AB của khúc sông cho bởi hình bên biết BC vuông góc BA; bc vuông góc CD ;M là trung điểm của BC và CD= 83 m

Cho đoạn thẳng BC, H là trùn điểm của đoạn thẳng BC. Qua H kẻ đường thẳng d vuông góc với BC. Trên đường thảng d lấy điểm A. Chứng minh tam giác AHB= tam giác AHC và AH là tia phân giác của góc BAC

1.     They (spend) ________ the night in the flooded area before help (arrive) _____________

2.     Last night, when I (arrive) _____________, they (have) _____________ dinner.

3.     Nam (not /buy) _____________ a new computer since he (sell) __________ the old one.

4.     By the time I (start) ________ primary school, I (learn) ___________ how to ride a bike.

5.     Yesterday Tuan (ask) _________________ me to go to the station with him, but I (not/want) ___________ to leave because I (wait) __________________ for a phone call.

6.     I (meet) _________ him in the park yesterday afternoon. He (read) _______ a newspaper.

7.     Hellen and Jack (play) ____________ games online when I locked on the door.

8.     Last night while I (watch) _____________ TV, my sister (do) ___________ crossword.

9.     Tomorrow, my father (go) ______ home as soon as he (finish) ____________ his work.

10.                        He (finish) ______________ the report by 9 o’clock last night.

11.                        Before she (come) ___________ tomorrow, we will have got everything ready.

12.                        When you (see) _________________ him tomorrow, you (recognize) ___________ him. He (wear) _______________________ a Yellow shirt.

13.                        The old man (fall) _______________ as he (get) ____________ into the bus yesterday.

14.                        He will write to me when he (arrive) _______________ in Hanoi next week .

15.                        When I (see) ________________ him in the park yesterday, he (sit) ______________ asleep in a chair.

16.                        Mr. Brown (phone) _______________ me as soon as he finishes his work tonight.

17.                        The light (go) ___________ out when we (study) _____________ our lesson last night.

18.                        Emergency workers (evacuate) __________ the village when the river flooded the area.

19.                        Mona says the children (play) _________________ in the garden when you arrive.

20.                        Whatever job you (decide) _________ to do in the future, I (support) ____________ you.

21.                        I can’t come to your party next Friday as I (work) ____________ on that day.

22.                        The mailman (come) ____________ while the Le family (sleep) _________ this morning.

23.                        They (not/speak) ____________to each other since they (quarrel) ________

24.                        When we (come) ____________ there yesterday morning, they (plant) ______________ some trees in the garden.

25.                        Since I last (see) ______________you,  I (be) ________________ ill.

26.                        Last night, while their parents (watch) __________ TV, their children (run) _____ about.

27.                        Why didn’t you listen while I (speak) _______________ to you?

28.                        I hope it (not/rain) ____________ when we (start) ________________ early tomorrow.

29.                        The movie (already/start) ________________ when I (arrive) ___________ last night.

30.                        Since I (move) ________________ here last year, I (work) _____________ for a bank.

31.                        All the students (sing) _________________ a merry song when I arrived.

32.                        He (sleep) ________________ so he did not understand what you said to him

33.                        I realized that I (not /study) ______________ hard enough for the examination.

34.                        You must tell me what you (do) _______________ since I last (see) _____________ you.

35.                        Last night, I (practice) _________ the piano while my brother (read) __________ a book.

36.                        By the time we (arrive) _____________ at the canyon, it (stop) ____________ snowing.

37.                        This morning when the clock (go) _______________ off I (leave) _________________ the bed immediately.

38.                        I (do) _____________ the washing up when the phone rang.

39.                        Most people (leave) ______________ before the volcano (erupt)  ________ last Sunday.

40.                        When Mrs. Brown looked out, she (see) _____________ her children playing near a pool.

41.                        Simon (get) _____________ lost because he (not/take) ____________ a map with him.

42.                        What _______________ you (do) ____________ when the mailman (come) ______________ to your house this morning?

43.                        Julia (make) _______________ over 30 movies since she moved to Paris.

44.                        My brother found the Old Friends website while he (surf) _____________ the internet.

45.                        This (happen) _______________ to Peter when he was working in the library.

46.                        My father felt better since he (move) _____________ to this town.

47.                        I (tell) ______________ you the lasted news as soon as I come back.

48.                        I (know) ______________ her since I moved to this neighborhood.

49.                        I (know) ______________ him when I worked in this factory.

50.                        I (find) ______________ my old pen after I (buy) _______________ a new one.

51.                        _______ you (watch) _____________ TV  as I (phone) ______________ you last night?

52.                        They looked at the balloon until it (disappear) ______________________

53.                        Since I (start) _______ learning English, I (have ) ____________ three different teachers.

54.                        Yesterday afternoon while I (water) _________ the garden, it (begin) ________ to rain.

55.                        I will wait for her until she (finish) ____________ her work.

56.                        Last night, when I (see) ___________ him on Le Duan street, he (run) __________ away.

57.                        As she (leave) ___________________ home tonight, she (call ) _____________ you.

58.                        We (just/get) _________________ o the plane when the pilot (tell) ________ us to get off again.

59.                         Yesterday afternoon, after he (finish) ________________ his work, he (come) ____________ home.

60.                        As soon as I (know) _________________ the result tomorrow, I (tell) _______________ you.