Những bài trên bn làm đúng rồi nhé. 
Writing
2.
1. went -> go
2. go -> went
3. harms -> harm
3.
1. He finds making model interesting.
2. I like the living room the best in the house.
3. She started learning English 3 years ago.
 

Cơ năng của viên đạn là:
\(W=0,1.\dfrac{100^2}{2}=500\left(J\right)\)
Áp dụng định luật bảo toàn năng lượng ta có:
\(W_đ+W_t=W\)
\(\Rightarrow\dfrac{mv^2}{2}+P.h=W\)
\(\Rightarrow\dfrac{0,1.60^2}{2}+0,1.10.h=500\)
\(\Rightarrow180+h=500\)
\(\Rightarrow h=320m\)
Vậy khi viên đạn còn vận tốc 60m/s thì độ cao viên đạn là 320m

-> The author of the novel "Ben nhau tron doi" is Coman.
Dịch: Tác giả của cuốn tiểu thuyết "Bên nhau trọn đời" là Coman.

Multiple choice
1. The new shopping centre ______ a lot of local people by their free music and fashion performances.  
A. attracts             B. attracting       C. attract     D. have attracted
2. Posting personal pictures on social media is fun; ______, sometimes it can bring many problems.
A. so                       B.although         C.however   D.but
3. ______ the grocery store closes, please remember to turn off the lights and lock the doors.
A. During                 B. Before           C. While       D.After
4. ______ the storm hit the town, volunteers gathered to clean up the debris.
A. While                   B. As soon as    C. Before     D. After 

1. collection
2. safety
3. exciting
4. healthy
5. easily
6. earache
7. classmate
8. traditional
9. performance
10. activities

Rearrange the words to make meaningful sentences.

1. my / used / favorite / is / shopping / for / books. / pastime
-> My favorite pastime is shopping for used books.

2. a / ate / too much / had / mai / she / stomachache / because / seafood.
-> Mai had a stomachache because she ate too much seafood.

3. voluntary / do / Young people / work / for / of / the benefits / the community.
-> Young people do voluntary work for the benefits of the community.

4. My friend / climbing. / is afraid / so / does not / enjoy / heights, / of / she / mountain
-> My friend is afraid of heights, so she does not enjoy climbing mountain.

5. the / volunteered / Last summer, / elderly / to / help / a / we / local / nursing home. / in
-> Last summer, we volunteered to help the elderdly in a local nursing home.

S + suggest + Ving: đề xuất làm j
S₁ + suggest + S₂ + (should) V: đề xuất ai đó làm j

-> We suggest cooking food for the elderly people.

Bài 2:

a, Xét tam giác ABC và tam giác CDA có:
AB = CD
AC chung
AD = BC
⇒ ΔABC = ΔCDA (c-c-c) (dpcm)
b, Do ΔABC = ΔCDA  ⇒ \(\widehat{BCA}=\widehat{DAC},\widehat{BAC}=\widehat{DCA}\) (cặp góc tương ứng)
mà: \(\widehat{BCA},\widehat{DAC}\) là 2 góc ở vị trí so le trong ⇒ BC//AD (dpcm)
       \(\widehat{BAC},\widehat{DCA}\) là 2 góc ở vị trí so le trong ⇒ AB // CD (dpcm)

Bài 1:

a, H là trung điểm của BC ⇒ BH = CH
Xét tam giác ABH và tam giác ACH có:
AB = AC
AH chung
BH = CH
⇒ ΔABH = Δ ACH (c-c-c) (dpcm)
b, Do ΔABH = Δ ACH ⇒ \(\widehat{AHB}=\widehat{AHC}\) (2 góc tương ứng)
mà \(\widehat{AHB}+\widehat{AHC}=180^o\) (do 2 góc kề bù)
\(\Rightarrow\widehat{AHB}+\widehat{AHB}=180^o\)
\(\Rightarrow2\widehat{AHB}=180^o\)
\(\Rightarrow\widehat{AHB}=180^o:2=90^o\) \(\Rightarrow AH\perp HB\) hay \(AH\perp BC\left(dpcm\right)\)