They looked healthy after the summer vacation

1. teaches

2. work

3. because

4. near

5. classes

6. finish

7. goes

8. home

9. watches

10. bed

Dear Mom and Dad ,

I arrived Da Lat and visited Lan'S penpal yesterday morning

I met her at the station, she took me to her house by her motorcycle

I am staying at Lan's house. I met her parents, they are very kind .

This morning, the weather was sunny and windy, we visited Cam Ly, she is beautiful and impressive

We ate tasty fruit in Da Lat

I took a lot of photos

I am happy to come here, I hope to visit it again

I will return Ha Noi next week

Công thức viết đúng: K₂O, FeSO₄, H₃PO₄.

Công thức viết sai: S₂O₄ sửa lại SO₂

Cu₂NO_3.........CuNO₃

Al₃O_{2 .............} Al₂O₃

Zn₂O_{2..............} ZnO

S₂O_{...................} SO₂

a. Phân tử khối của axit sunfuric: 2.1+32+4.16=218 (đvc)

b. Phân tử khối của khí acmoniac: 14+3.1= 17 (đvc)

c. Phân tử khối của canxi cacbonat: 40+12+3.16= 100 (đvc)