8. Plural of knife : knives

a) D
b) B

1. The sights of the city never fail to impress foreign tourists.
2. It's necessary for everybody to clean up their neightborhood once a week.
3. Children in this poor village are allowed to go to school without tuition fee.
4. Although Wnglish is their official language, most of them can speak Chinese.
5. We wish today were sunny so that we could spend the day in the coutnryside.

1. D: món ăn nhẹ
2. B: thức ăn (đựng trong đĩa)
3. D
4. B: hạt 
5. D: nước ngọt

1. famous
2. operation
3. energetically
4. strength
5. different

inconvenient

6. B
7. C
8. A

Red __symbolizes__ danger (symbol )
We have to __improve__ all the schools in the city (improvement)

colorful

modernized