Choose the best answer: 

1. What........... you do if you won a lottery ticket? 

A.will       B.would        C. Did           D.do 

2. My daughter is very.................... in picture book.

A.interest                          B. interesting     

C.interested.                     D.interests 

3. The................in Kobe in 1995 caused severe damage.

A.typhoon                          B.volcano 

C.snowstorm                     D.earthquake 

4. We should use paper as.................as we can.

A.economy                         B.economic 

C.economical                     D.econonically

5. Na is very tired.   ................, she has to finish her homework before she goes to bed.

A.but         B.so        C.however           

D. Therefore 

6. I think I lost my new pen. I've.............it everywhere and I can't find it anywhere.

A.looked for                    B.taken care of 

C put on                           D. Turned off 

7. You should have a ( an ) ............... check your motorbike regularly. 

A.plumber                         B.carpenter

C.mechanic                      D.electrician 

8. They arrived..............London on time.

A.at          B.in          C.to          D.from

9. John asked me..............that film the night.

A.that I saw                   B.had I seen

C.if I had seen               D.if had I seen 

10. - What will we do today? 

      -  Let's go for a walk,.............?

A.do you                        B.shall we 

C. Do we                         D.don't you 

11. - Do you want to wait? 

      - Two weeks................. too long for me to wait. 

A.is        B.are          C.were         D.was

12.  - Would you like milk or sugar? 

        - ...............................................

A.no sugar, please

B.no, just a black coffee, please

C.why not milk for me?

D.yes, a lot of milk    

Để phân số là số nguyên thì

21n+1 chia hết cho 14n+3

\(\Leftrightarrow3\left(14n+3\right)-2\left(21n+1\right)\) chia hết cho 14n+3

\(\Leftrightarrow42n+9-42n-2\) chia hết cho 14n+3

<=> 7 chia hết cho 14n+3

Mà 14n chia hết cho 7

3 không chia hết cho 7

=> 14n+3  không chia hết cho 7

=> \(n\in\varnothing\)

Goi ƯCLN(2n+1;3n+1) là d

=> \(3\left(2n+1\right)-2\left(3n+1\right)\) chia hết cho d

=> \(6n+3-6n-2\) chia hết cho d

=> 1 chia d

=> d\(\inƯ_{\left(1\right)}\)

=> d=1 ; d= - 1

Mà d lớn nhất

=> d=1

Đặt BT là A

\(\Rightarrow A=2016-\left(\frac{1}{1.2.6}+\frac{1}{2.3.6}+\frac{1}{3.4.6}+....+\frac{1}{19.20.6}\right)\)

\(\Rightarrow A=2016-\frac{1}{6}\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+....+\frac{1}{19}-\frac{1}{20}\right)\)

\(\Rightarrow A=2016-\frac{1}{6}\left(1-\frac{1}{20}\right)\)

\(A=2016-\frac{1}{6}.\frac{19}{20}=2016-\frac{19}{120}=\frac{241901}{120}\)

chả bik

có hoặc 0 ; 0 hoặc có

Ta có

(+) \(n\ne7\) để phân số có nghĩa

(+) Phân số tối giản 

<=> 2n+3 không chia hết cho n+7

<=> 2(n+7) - (2n+3) không chia hết cho n+7

<=> 2n+7 - 2n - 3 không chia hết cho n+7

<=> 4 không chia hết cho n+7

\(\Rightarrow n+7\notin\left\{1;2;4;-1;-2;-4\right\}\)

\(\Rightarrow n\notin\left\{-6;-5;-3;-8;-9;-11\right\}\)

Vậy để phân số tối giản thì \(n\notin Z\) ; \(n\notin\left\{-6;-5;-3;-8;-9;-11;7\right\}\)

hàm số j bn

ta có:\(\frac{3}{4}=\frac{30}{40},\frac{3}{5}=\frac{3}{50}\)

3 phân số nằm giữa là \(\frac{31}{40},\frac{32}{40},\frac{33}{40}\)

  1. You can find the physics books......at...... the back of the library.

  2. The United States' Library of Congress is.........in...... Washington Dc. 

Checkpoint 1: Each of them ___________ a different character. (A: have     B: To have           C: having        D: has)

Checkpoint 2: The audience didn't laugh ___ his joke. (A: at         B: on             C: to           D: for)

Checkpoint 3: Her new glasses change her ____. (A: appear         B: appears         C: appearance          D: appearances)

Checkpoint 4: A child whose parents have died is called a(n) ____. (A: nephew         B: cousin         C: neighbor          D: orphan)

Checkpoint 5: The lost girl has_________ (A: Short black hair            B: a short black hair         C: hair short black          D: All are correct)

Checkpoint 6: Don't come in. Please wait ______ for a few minutes (A: inside       B: outside          C: insides          D: outsides)

Checkpoint 7: Let's go out for meal.-________. (A: Yes, I am sorry              B: I'd love to             C: Thanks, Idon't go                D: You're welcome

Checkpoint 8: How about _________ the clothes (A: wash           B: to wash           B: washing           C: washes)