1 A

2 D

3 B

4 D

5 A

6 D

7 C

8 A

9 C

10 B

11 D

IV

12 went

13 is playing

14 closing

15 don't drink

16 would visit

17 B

18 D

19 B

20 D

21 cook

22 it

23 his

24 On

25 him

26 because

27 B

28 D

29 C

30 B

31 A

VIII

1 Janet isn't interested in watching sports on TV

2 I Think you should go to school by bike

3 Lake Baikal is the deepest lake in the world

4 He doesn't have enough time to complete the test

5 The last time he visited HLB is 5 years ago

IX 

37 In dry season there is alway a lack of water

38 Yesterday he was so tired that he didn't finish his work

39 There are 10 fingers and two arms on the body

40 What kind of TV programme do you like to watch the most when you were small?

I

1.What type of energy do you use at home?
2.John uses low energy light bulbs to save electricity.
3.Mai can't go to the cinema at present because she is studying for her exam.
4.What book are you currently reading?
5.She is not swimming in the swimming pool at the moment.
6.Scientists are looking for a new energy source to replace coal now

II.

1. Coal is more expensive and more polluting than natural gas.

2. We are looking for cheap and clean and effective sourced of energy..

3.. You should switch off electrical appliances when they aren’t in use.

4. Despite being the most polluting of fossil fuels, coal is still the largest sources of energy worldwide.

5. People will use biogas for fuel in homes and for transport

1 create $\rightarrow$ c. energy (tạo ra năng lượng)

2 drive $\rightarrow$ a. machinery (vận hành máy móc)

3 generate $\rightarrow$ e. electricity (phát/tạo ra điện)

4 turn $\rightarrow$ b. turbines (quay tua-bin)

5 heat $\rightarrow$ d. houses (sưởi ấm nhà cửa)

b

1 How many types of energy sources are mentioned in the text? What are they?
$\rightarrow$ Two types of energy sources are mentioned. They are renewable and non-renewable energy sources. (hoặc kể tên cụ thể: fossil fuels/coal/oil, hydro power, nuclear power, wind power, solar power)

2 What are the disadvantages of hydro and nuclear power?
$\rightarrow$ Hydro power is expensive to build dams, and nuclear power can be very dangerous.

3 Why do you think the wind and the sun are called alternative sources of energy?
$\rightarrow$ Because they are clean, renewable, and can be used instead of non-renewable sources (fossil fuels).

4 What types of energy does Viet Nam use most?
$\rightarrow$ Viet Nam uses hydro power and fossil fuels (coal, gas, oil) most.

5 What does the professor think Viet Nam will use more in the future?
$\rightarrow$ He thinks Viet Nam will use more renewable energy sources like solar and wind power in the future.

– Thân to ra do sự phân chia các tế bào của mô phân sinh: tầng sinh vỏ, tầng sinh trụ. ... Hằng năm sinh ra phía ngoài một lớp tế bào vỏ, phía trong một lớp thịt vỏ. + Tầng sinh trụ nằm giữa mạch rây và mạch gỗ, hằng năm sinh ra phía ngoài một lớp mạch rây, phía trong một lớp mạch gỗ, bóc theo vỏ.

#CHUCBANTHITOT

Gấp lắm rùi. Các bạn giải nhanh lên nhé.

a) nếu \(5x-3\ge0\)hay \(x\ge\frac{3}{5}\) ta có \(\left|5x-3\right|=5x-3\)

nếu \(5x-3< 0\) hay \(x< \frac{3}{5}\) ta có \(\left|5x-3\right|=3-5x\)

với \(x\ge\frac{3}{5}\) ta có

\(\left|5x-3\right|=x+7\) \(< =>5x-3=x+7\)

                                           \(< =>5x-x=7+3\)

                                            \(< =>4x=10\)

                                             \(< =>x=\frac{10}{4}=\frac{5}{2}\) (thoả mãn khoảng xét: \(\frac{5}{2}>\frac{3}{5}\))

với \(x< \frac{3}{5}\)ta được

\(\left|5x-3\right|=x+7\) \(< =>3-5x=x+7\)

                                          \(< =>-5x-x=7-3\)

                                          \(< =>-6x=4\)

                                          \(< =>x=-\frac{4}{6}=-\frac{2}{3}\) (thoả mãn khoảng xét : \(-\frac{2}{3}< \frac{3}{5}\))

b) bạn lập bảng xét dấu rồi xét từng trường hợp là được

Me: What are you doing on Sunday afternoon?

Friend: I’m not doing anything. / Nothing much.

Me: Do you want to see a movie with me?

Friend: Sure. What movie is it?

Me: It's "The Journey to Mars".

Friend: What time does it start?

Me: It starts at 4 p.m.

Friend: Great! See you then.

Me: What are you doing on Saturday morning?

Friend: I’m free.

Me: Would you like to go to the movies with me?

Friend: Sounds good. What movie do you want to watch?

Me: How about "The Forest Book"?

Friend: What time is it on?

Me: It's at 10 a.m.

Friend: OK, let's meet at the cinema at 9:45.

Bài 3:

a: ΔABC cân tại A

mà AH là đường cao

nên H là trung điểm của BC

=>\(CH=HB=\frac{CB}{2}\)

Xét ΔCKB vuông tại K và ΔCHA vuông tại H có

\(\hat{KCB}\) chung

Do đó: ΔCKB~ΔCHA

=>\(\frac{CB}{CA}=\frac{BK}{HA}=\frac{38.4}{32}=\frac65\)

=>\(\frac{CH}{CA}=\frac35\)

=>\(\frac{CH}{3}=\frac{CA}{5}=k\)

=>CH=3k; CA=5k

ΔAHC vuông tại H

=>\(AH^2+HC^2=AC^2\)

=>\(AC^2-CH^2=AH^2\)

=>\(\left(5k\right)^2-\left(3k\right)^2=32^2\)

=>\(16k^2=1024\)

=>\(k^2=64=8^2\)

=>k=8

=>\(CA=5\cdot8=40\left(\operatorname{cm}\right)\) ; \(CH=3\cdot8=24\left(\operatorname{cm}\right)\)

ΔABC cân tại A

=>AB=AC

=>AB=40(cm)

H là trung điểm của BC

=>\(BC=2\cdot CH=2\cdot24=48\left(\operatorname{cm}\right)\)

b: Xét ΔOHB vuông tại H và ΔOHC vuông tại H có

OH chung

HB=HC

Do đó: ΔOHB=ΔOHC

=>OB=OC

O nằm trên đường trung trực của AC

=>OA=OC

=>OA=OB=OC

=>O là tâm đường tròn ngoại tiếp ΔABC

Xét ΔABC có \(cosBAC=\frac{AB^2+AC^2-BC^2}{2\cdot AB\cdot AC}\)

\(=\frac{40^2+40^2-48^2}{2\cdot40\cdot40}=\frac{1600+1600-2304}{2\cdot1600}=\frac{896}{3200}=\frac{28}{100}=\frac{7}{25}\)

=>\(\sin BAC=\sqrt{1-\left(\frac{7}{25}\right)^2}=\frac{24}{25}\)

Xét (O) có \(\hat{BAC}\) là góc nội tiếp chắn cung BC

=>\(\hat{BOC}=2\cdot\hat{BAC}\)

=>sin BOC=\(\sin\left(2\cdot\hat{BAC}\right)=2\cdot\sin BAC\cdot cosBAC\)

\(=2\cdot\frac{7}{25}\cdot\frac{24}{25}=\frac{336}{625}\)

=>\(cosBOC=\sqrt{1-\left(\frac{336}{625}\right)^2}=\sqrt{\left(1-\frac{336}{625}\right)\cdot\left(1+\frac{336}{625}\right)}\)

\(=\sqrt{\frac{289}{625}\cdot\frac{961}{625}}=\frac{17}{25}\cdot\frac{31}{25}=\frac{527}{625}\)

Xét ΔBOC có \(cosBOC=\frac{OB^2+OC^2-BC^2}{2\cdot OB\cdot OC}\)

=>\(\frac{OB^2+OB^2-48^2}{2\cdot OB\cdot OB}=\frac{527}{625}\)

=>\(2\cdot OB^2-48^2=2\cdot OB^2\cdot\frac{527}{625}\)

=>\(2\cdot OB^2\left(1-\frac{527}{625}\right)=48^2\)

=>\(2\cdot OB^2\cdot\frac{98}{625}=48^2\)

=>\(OB^2\cdot\left(\frac{14}{25}\right)^2=48^2\)

=>\(OB\cdot\frac{14}{25}=48\)

=>\(OB=48:\frac{14}{25}=48\cdot\frac{25}{14}=24\cdot\frac{25}{7}=\frac{600}{7}\)

=>\(OC=\frac{600}{7}\left(\operatorname{cm}\right)\)

ΔOHC vuông tại H

=>\(OH^2+HC^2=OC^2\)

=>\(OH^2=\left(\frac{600}{7}\right)^2-24^2=\frac{360000}{49}-576=\left(\frac{576}{7}\right)^2\)

=>\(OH=\frac{576}{7}\) (cm)

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