V. Sắp xếp các từ xáo trộn thành câu hoàn chỉnh.

1. The/United States/one/largest/the/of/is/Library/world's congress/library.

=> The United States library is one of the largest world's congress library.

2. Receives/the/Congress/Library/of/copies/all/American/book.

=> The congress library receives all of copies American books.

3. Employees/work/5000/library/that/in.

=> 5000 employees work in that library.

4. The/books/are/lot of/ in /there/a/library.

=> There are a lot of books in the library.

5. The/borrow/books/can/students/from/library.

=> The students can borrow books from library.

6. Of/kinds/many/put/are/shelves/on/books/the.

=> Many kinds of books are put on the shelves.

7. Usually/literature/Mondays/we/on/have/Fridays/and.

=> We usually have literature on Mondays and Fridays.

1. What is your age?

2. His age is twelve.

3. I left school at the age of 18.

pronunciation

Hai hạt bụi trong không khí, mỗi hạt chứa 5 . 10 8  electron cách nhau một khoảng r. Lực đẩy tĩnh điện giữa hai hạt bằng 1 , 44 . 10 - 7 N .  Tính r.

A. 1 cm.

B. 4 cm.

C. 2 cm.

D. 3 cm.

Thể tích V của khối tròn xoay thu được khi quay xung quanh trục Ox hình phẳng giới hạn bởi các đường y   =   x ln x , x=e và trục hoành là.

Trong không gian với hệ trục tọa độ Oxyz cho điểm A(2;-2;2) và mật cầu (S): x 2 + y 2 + ( z - 1 ) 2 = 4 . Điểm M di chuyển trên mặt cầu (S) đồng thời thỏa mãn O M → . A M → = 6 . Điểm M luôn thuộc mặt phẳng nào dưới đây?

      much      playing      relax           fast food             movies

after school          Let's        computer games     homework 

 K: Hello An. What are you doing ?

 A: Hi, Kha. I'm doing my math(1) homework.

 K: you work too(2) much, An. You should (3) relax It's five and tommorow is SunDay 

 A; Ok. what should we do this evening?

 K:What about going to the (4) movies ?

 A: There aren't any good movies on at the moment. (5) Let's go swimming and eat in (6) fast food restaurant.

 K: It's a good idea!

 A: Where is Bao? Let's invite him, too.

 K:Oh, Bao is in the music room. He's learning to play the (7) piano He practices everyday (8) after school.

  A: Kha, what do you usually do after school?

 K: I usually play some (9) sports.

 A: Do you play sports ? 

 K: Oh, yes. I play volleyball for the school team. We always need more players. Why don't you come along?

 A: I don't like volleyball. I enjoy (10) playing badminton

a/ = 1,7 +1,7 +...+1,7 [19 số 1,7] 

 = 1,7 x 19 = 32,3

b/ = 2,3 +2,3 +...+2,3 [23 số 2,3]

 = 2,3 x 23 =52,9

a) PTHH: 2Mg + O₂ -> 2MgO

b) PT bảo toàn khối lượng: m_Mg + m_O2 = m_MgO

c) Theo câu b ta có: m_O2 = m_MgO - m_Mg = 15 - 9 = 6(g)