III

1 went

2 often goes

3 didn't do

4 doesn't do

5 often talk

6 Did you talk

7 didnt speak

8 doesn't speak

9 did she live

10 do you live

11 did you last meet

12 meets

13 am - eat

14 was

15 sells

16 sold

17 often wait

18 waited

19 visited

20 did - visit

IV

1 failed

2 has taught

3 haven't finished

4 finished

5 didn't speak

6 sold

7 has lived

8Have you already done

9 has she lived - left

10 haven't found - left

11 did - see

12 have waited

13 has been

14 has met

15 has taught

16 took

17 Did - tell

18 didn't come

19 did - go

20 has already drunk

1.went

2.often.goes

3.didn't.do

4.has.not.did

5.often.talk

(máy.tính.bị.hỏng.dấu.cách.nên.thay.bằng.dấu.chấm.nhá,thông.cảm)

1. will visit    -   will give   - will become   - will speak     -      will sell    -    will wait     -    Will you leave    -      does she live     -      will you live         -       will you meet         - wait              - Is your sister sick?             -         Does he usually meet          - teaches     -     takes

16. Will you tell       -       don't come     -      does your family       -     will visit

1. had finished - went

2. had seen - left

3. were - had left - arrived

4. came - had started

5. had flown - were

6. Had he driven - happened

7. had come - left

8. had done - went

9. had she lived - moved

10. did - had learnt

11.  had said - got

12. had waited - gave

13. Were your sister sick after she had eaten that cake?

So sánh hơn

1 taller

2 younger

3 more

4 father

5 harder

6 worse - cheaper

7 fewer

8 better

9 more

10 taller than

Tính từ dàu

1 better

2 more difficult

3 more intelligent

4 more dangerous

5 more popular

6 more beautiful

7 more difficult

8 more pleasant

9 more popular

10 more interesting

So sánh bằng

1 as tall as

2 not as intelligent as

3 as good as

4 as large as

5 as hot as

6 as fast as

7 as young á

8 as easy as

9 as addictive as

10 as well as

So sánh kém

1 less expensive than

2 less intelligent than

3 less milk

4 less difficult 

5 less interesting

So sánh nhất

Tình từ ngắn

1 the oldest

2 the highest

3 the worst

4 best

5 longest

6 highest

7 easiest

8 busiest

9 nicest

10 noisiest

Tính từ dài

1 the most intelligent

2 most popular

3 the most expensive

4 most dangerous

6 most important

7 most beautiful

Theo thứ tự đúng là từ dưới lên nhé.

a: \(P=\dfrac{x\sqrt{2}-\sqrt{x}+\sqrt{2x}-1+2x+\sqrt{2x}+x\sqrt{2}+\sqrt{x}-2x+1}{2x-1}:B\)

\(=\dfrac{2x\sqrt{2}+2\sqrt{2x}}{2x-1}:\dfrac{2x-1+x\sqrt{2}-\sqrt{x}+\sqrt{2x}-1-2x-\sqrt{2x}-x\sqrt{2}-\sqrt{x}}{2x-1}\)

\(=\dfrac{2\sqrt{2x}\left(\sqrt{x}+1\right)}{2x-1}\cdot\dfrac{2x-1}{-2-2\sqrt{x}}\)

\(=\dfrac{2\sqrt{2x}\left(\sqrt{x}+1\right)}{-2\left(\sqrt{x}+1\right)}=-\sqrt{2x}\)

b: Khi x=1/2(3+2căn2) thì \(P=-\sqrt{2\cdot\dfrac{1}{2}\left(3+2\sqrt{2}\right)}=-\sqrt{2}-1\)

Đáp án C

Thanh nhựa sẫm mầu nhiễm điện âm vì cọ xát vào vải khô.

Thanh nhựa sẫm màu (nhiễm điện âm) hút quà cầu xốp (đã nhiễm điện) →quả cầu xốp có nhiễm điện dương. Vì hai vật nhiễm điện khác loại thì hút nhau.

b,c là đáp án đúng đó