1. She asked Minh if / whether he could speak Spanish

2. ​Thanh asked her teacher if / whether she would finish her exercise at home

3. Nien asked Hoa if / whether she had many new friends

4. They asked us if / whether we had to go then

5.  They said to us if / whether we had to go then

6. I asked Nam if / whether he was free tonight

7. She asked me if / whether I knew the way to the station

8. John asked Nhi if / whether Phong Nha was in southern Vietnam

9. The visitors asked if / whether they could take photos 

10. Daniel asked Jim if / whether there was a cafe nearby

a: Xét ΔADH vuông tại H và ΔBDA vuông tại A có

\(\widehat{ADH}\) chung

Do đó: ΔADH∼ΔBDA

b: Xét ΔHAD vuông tại H và ΔHBA vuông tại H có 

\(\widehat{HAD}=\widehat{HBA}\)

Do đó: ΔHAD∼ΔHBA

Suy ra: HA/HB=HD/HA

hay \(HA^2=HB\cdot HD\)

a) Xét \(\Delta ADH\) và \(\Delta BDA:\)

\(\widehat{H}=\widehat{A}\left(=90^o\right).\)

\(\widehat{D}\) chung.

\(\Rightarrow\Delta ADH\sim\Delta BDA\left(g-g\right).\)

b) Xét \(\Delta BDA\) và \(\Delta BAH:\)

\(\widehat{BAD}=\widehat{BHA}\left(=90^o\right).\)

\(\widehat{B}\) chung.

\(\Rightarrow\Delta BDA\sim\) \(\Delta BAH\left(g-g\right).\)

Mà \(\Delta ADH\sim\Delta BDA\left(cmt\right).\)

\(\Rightarrow\Delta ADH\sim\Delta BAH.\)

\(\Rightarrow\dfrac{AH}{BH}=\dfrac{DH}{AH}\) (2 cạnh tương ứng).

\(\Rightarrow AH^2=DH.BH.\)

\(Errink \times Cream\)

I

1. c

2. d

3. b

4. d

5. d

II

1. a (trọng âm rơi 2 còn lại rơi âm 3)

2. b (trọng âm rơi 2 còn lại rơi âm 1)

3. c (trọng âm rơi 2 còn lại rơi âm 1)

4. d (trọng âm rơi 3 còn lại rơi âm 2)

5. a (trọng âm rơi 2 còn lại rơi âm 1)

IX

1. a

2. a

3. c

4. a

5. a

Bài I, II tớ làm bên dưới roi. Có gi k thắc mắc ib tớ nha.

11. A. living room         B. hall                          ​  C.flat                      D. kitchen

12. A. picture                B. shower                     C. bathroom                  D. toilet

13. A. decorate              B. envelope                  C. repaint                       D. decoration

14. A. big                     B. tall                           C. wide                         D. expensive

15. A. cross                  B. turn                          C. straight                     D. buy

16. A. sunny                B. beaches                    C. sand                         D. supermarket

17. A. picture                B. shower                     C. bathroom                  D. toilet

18. A. forest                  B. mountain                  C. lake                           D. city

19. A. walk                   B. compass                   C. plaster                      D. sleepingbag

20. A. mountain             B. valley                       C. cave                         D. club

21. A. rooster               B. writer                       C. gamer                       D. swimmer

22. A. blossom              B. apricot                      C. shopping                  D. flower