Unit 4 Keeping Clean More reading and writing 课件（共14张PPT）.pptx
Unit 4 Keeping Clean
More
reading and wrting
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单元新知
More reading and writing
Look, listen, and read.
1
Old London and London Today
In the old days, London was a city with dirty air. Today the air in London is better and clean. The sky is clear on a sunny day!
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