1. D 

( both traffic jams and pollution are identified as big problems in the city)

2. A

The passage states that traffic jams occur when there are too many cars on the roads, making it difficult for people to move around quickly. 

3. C

According to the passage, cities can reduce traffic congestion by encouraging people to use public transportation like buses or trains instead of driving their own cars.

4. B 

The passage suggests that a solution for pollution in cities is to plant more trees and create more green spaces. 

5. C

 Trees provide oxygen and clean the air, as mentioned in the passage.

6. D

by using public transportation....can make our city environment....