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1/

1. Carbon footprint 

2. Excavation 

3. Intact 

4. Academic 

5. Undergraduate 

2/

1. Further 

2. Lower 

3. Heat-related 

4. Scenic 

5. Cultural 

3/

1. Having lived near a chemical plant for many years, some villagers have now developed cancer.

2. Having attended a conference on nature conservation, Quang became more involved in environmental activities. 

3. Mai regretted having dumped / dumping rubbish in the country park near her house.

4. The manager denied having allowed / allowing harmful gases to emit into the air from the factory.

5. They suspected Tom of having used / using explosives to kill fish in the lake.

4/

1. Has been studying 

2. Have you taken 

3. Have been learning 

4. Has been living 

5. Has finished