1. Nam worked well , did he ?
--> didn't he
2. A lot of culture and artistic activities are held as part of the flower Festival in Da Lat
--> cultural
3. In the future , we will use environment- friendly means of transport
--> friendly environment
4. Diseases spread very quickly in overcrowd areas
--> overcrowded
5. You have hear about that , don not you
--> haven't you
6. We should use public transport when we travel long distances
--> transports
7. Carbon footprint is the positive effects x we have on the environment
--> that
8. He will not fall down , does he ?
--> will he
9. Coal , oil and natural gas are unlimited so we should use alternative sources of energy in the future
--> will
10. He used to beat his wife , did he
--> didn't he?