Ô tô đang chuyển động với tốc độ 36km/h thì tài xế tăng ga cho xe chuyển động thẳng nhanh dần đều, sau 5s ô tô đạt tốc độ 72km/h.

a. Tính gia tốc của ô tô?

Sau 20s chuyển động, tài xế cho xe giảm phanh chuyển động chậm dần đều, sau 10s thì dừng hẳn. Tính quãng đường ô tô đi được từ lúc giảm phanh đến lúc dừng hẳn.

Read the passage below carefully, and then choose the best answer:

Background, in relation to computers, on the screen, the color on which characters are displayed. (1) _______, a white background may be used for black characters. In a windowing environment in which more than one program or document can be available to the user, open but currently inactive (2) _______ are said to be in the background.

In the context of operating systems and program execution, background refers to a process, or task, assigned a lower priority in the microprocessor's share of time to tasks other than the task running in the (3) _______. A background process thus often performs its work, such as printing or checking for arriving messages on an electronic mail network, invisibly unless the user requests an update or brings the task to the foreground. (4) _______, only multitasking operating systems are able to support background processing. However, some operating systems that do not support multitasking may be able to perform one or more types of background tasks. For example, in the Apple Macintosh operating system running in Single-Launch Mode (with multitasking (5) _______), the Background Printing option can be used to print documents while the user is doing other work.

Câu 2:
A. windows
B. systems
C. tasks
D. characters

bài 1: Hòa tan 10 g hỗn hợp 2 kim loại Zn và Ag vào dung dịch HCl dư, sau phản ứng thu đc một lượng chất rắn A và 2,24 lít khí.

a) Xác định chất rắn A

b) Tính khối lượng mỗi KL có trong hỗn hợp ban đầu 

diện tích khu rừng ngập mặn là 15ha trong đó 1/2 diện tích trồng đước.diện tích trồng đước là bao nhiêu mét vuông

. Một ô ô chuyển động đều theo đường tròn bán kính 100 m với gia tốc hướng tâm 2,25 m/s2 . Tốc độ dài của ô tô có giá trị:

Exercise 1. Make the positive or negative past perfect. 

1) When I arrived at the cinema, the film _______________(start).
2) She _____ (live) in China before she went to Thailand.
3) After they _____(eat) the shellfish, they began to feel sick.
4) If you ____ (listen) to me, you would have got the job.
5) Julie didn't arrive until after I _______(leave).
6) When we _______ (finish) dinner, we went out.
7) The garden was dead because it ______ (be) dry all summer.
8) He _______ (meet) her somewhere before.
9) We were late for the plane because we ______ (forget) our passports.
10) She told me she _____ (study) a lot before the exam.
11) The grass was yellow because it ____ (rain) all summer.
12) The lights went off because we _____ (pay) the electricity bill.
13) The children ______ (do) their homework, so they were in trouble.
14) They ____ (eat) so we went to a restaurant.
15) We couldn't go into the concert because we ____ (bring) our tickets.
16) She said that she ______ (visit) the UK before.
17) Julie and Anne _____ (meet) before the party.
18) I _____ (have) breakfast when he arrived.
19) He ______ (use) email before, so I showed him how to use it. 
20) You (study) for the test, so you were very nervous.

Exercise 2. Make past perfect simple ‘yes / no’ or ‘wh’ questions: 

1. _______________________ (you / go) there before we went together? 

2. _______________________ (she / see) the film already? 

3. Why _______________________ (he / forgot) about the meeting? 

4. _______________________ (it / be) cold all week? 

5. _______________________ (I / read) the book before the class? 

6. When she arrived, _______________________ (we / eat) already? 

7. Where _______________________ (you / be) when I saw you? 

8. _______________________ (they / travel) by bullet train before? 

9. _______________________ (John / meet) Lucy before they went on holiday together? 

10. _______________________ (you / do) your homework before I saw you? 

11. Where _______________________ (she / work )? 

12. _______________________ (I / pay) the bill before we left? 

13. _______________________ (we / visit) my parents already that winter? 

14. When you called, _______________________ (they / eat) dinner? 

15. How _______________________ (he / manage) to fix the cooker? 

16. _______________________ (my sister / be) sick for a long time? 

17. How much _______________________ (she / study) before the exam? 

18. What _______________________ (you / cook) for dinner that night? 

19. When _______________________ (they / arrive)? 

20. How many coffees _______________________ (she / drink) before the interview?

số 3510 được biễu diễn trong hệ cơ số 2 là ?

cho mình cách giải với