đánh trọng âm thì tất nhiên phải có quy tắc chứ ! Không theo quy tắc mà đánh đúng thì một là đánh theo cảm tính , hai là theo thói quen thôi . Từ ''important '' rơi vào âm thứ hai

1. am watching

2. to turn

3. spend / playing

4. listening

5. goes / eats

6. is going to stay

7. get

8. didn't go / caught

1. Life in the city is always busy .

2. Don't spend too much of your time playing video games.

3. Video games can be addictive , so player must be careful.

4. Children should take part in outdoors activities with friends.

5. She will get used to the noise of the traffic soon.

6. Children shouldn't often go to the amusement center.

1. T

2. F

3. T

4. F

5. T

6. F

1+1+1+1+1+1.0+1 = 6

1. c

2, a

3. c

4. c

5. c

6, b

7. b

8. a

9. a

10. c

c, Xét tam giác ABC vuông tại A(gt)

\(\Rightarrow\) BC^2 = AB^2 + AC^2 ( theo định lí Py-ta-go)

\(\Rightarrow\) BC^2 = 6^2 + 8^2

\(\Rightarrow\) BC^2 = 100

\(\Rightarrow\) BC= 10(cm)

\(\dfrac{AB}{BH}\) = \(\dfrac{BC}{AB}\) ( chứng minh trên )

\(\Rightarrow\) \(\dfrac{6}{BH}\) = \(\dfrac{10}{6}\)

\(\Rightarrow\) BH = \(\dfrac{6.6}{10}\)

\(\Rightarrow\) BH = 3,6 (cm)

\(\dfrac{Sabh}{Sabc}\) = \(\dfrac{\dfrac{1}{2}AH.BH}{\dfrac{1}{2}AH.BC}\) = \(\dfrac{BH}{BC}\)

\(\Rightarrow\) \(\dfrac{Sabh}{Sabc}\) = \(\dfrac{3,6}{10}\) = \(\dfrac{9}{25}\)

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tổng của 3 số đó là : 42