A. making a difference B. to make a difference C. made a difference D. make a difference
A. reducing B. to be reduced C. reduced D. to reduce
A. to visit Tianjin B. visited Tianjin C. to have visited Tianjin D. to be visited Tianjin
A. carpool B. to carpool C. carpooling D. being carpooled
A. Plant trees, reduce B. Planting trees, to reduce C. To plant trees, reduce D. Planting trees, to reducing
A. Take a hike B. Taken a hike C. Taking a hike D. Having taken a hike
A. keep B. kept C. keeps D. keeping
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