Planting trees can contribute to reducing global warming.

A. We decided to reduce carbon footprints before seeing people suffer global warming consequences.

B. We saw people suffer global warming consequences after we decided to reduce carbon footprints.

C. We decided to cut down on carbon footprints after we saw people suffer global warming consequences.

D. We decided to cut down on carbon footprints before we saw people suffer global warming consequences.

A. Heat-related illnesses result from the increase in earth's temperature.

B. Heat-related illnesses result in the increase in earth's temperature.

C. Heat-related illnesses lead to the increase in earth's temperature.

D. Heat-related illnesses trigger the increase in earth's temperature.

A. Carbon dioxide is the only greenhouse gas that causes global warming.

B. Global warming results in greenhouse gases, including carbon dioxide.

C. One of the main greenhouse gases that lead to global warming is carbon dioxide.

D. Global warming causes greenhouse gases, including carbon dioxide.

A. Some scientists were accused of having falsify the effects of climate change.

B. Some scientists were accused of having been honest about the effects of climate change.

C. Although some scientists have distorted the effects of climate change, they were not accused.

D. Some scientists were accused of having falsified the effects of climate change.

A. Unless he donated a lot of money to environmental protection campaigns, he was admired.

B. He was admired for having donated a lot of money to environmental protection campaigns.

C. If he had donated a lot of money to environmental protection campaigns, he would have been admired.

D. If he donates a lot of money to environmental protection campaigns, he will be admired.

A. We can no longer remember having advised you on how to decrease your energy use.

B. We remember having advised you on how to maintain your energy use.

C. We remember having advised you on how to decrease your energy use.

D. We remember to have advised you on how to decrease your energy use.