1. Trang (not write) didn't write to her parents last week. She (phone) is phoning them now
2. Lien's brother is an architect but he (not work) isn't working at the moment.

3. How much does it usually (cost) cost to mail a letter to England?

4. They (travel) will travel to the USA next month

\(\dfrac{42}{46}+\dfrac{250}{186}+\dfrac{-2121}{2323}+\dfrac{-125125}{143143}\)

\(=\dfrac{21}{23}+\dfrac{125}{143}+\left(\dfrac{-21}{23}\right)+\left(\dfrac{-125}{143}\right)\)

\(=\dfrac{21}{23}+\dfrac{125}{143}-\dfrac{21}{23}-\dfrac{125}{143}\)

\(=0\)

a.so lien truoc 160 la

a.161

b.150

c.159

d.170

b.mot cai ao vuông co 6m.Chu vi cua hinh vuông đo la

a.24m

b.36m

c.10m

d.12

1. The lecturer is giving us first-aid instruction.

Nhận xét:

Quy luật:

Số hạng thứ  là:  với 

Vậy:

+) Số hạng thứ  là: 

+) Số hạng thứ  là: 

Sô thứ 6 là: 274

Số thứ 7 là: 560

Tôi muồn ăn mọi thứ 

=> I want to eat everything.

 Birds (build) build  their nests in the Summer and (fly) fly to the Sound in the Winter. 

44. While I (write) was writing a letter, the children (play) were playing outside yesterday. 

1. colder

2. more important

3. thinner

4. more crowded

5. higher

6. more friendly

7. worse

8. more exciting

9. narrower