《They sometimes work harder》Life now and then PPT课件3
《They sometimes work harder》Life now and then PPT课件3第3页

environment

In the past There was fewer tall buildings. The mountains were greener. The rivers were cleaner and there were more fish swimming in the rivers.

At present Tall buildings take up more room for crops. The air is not so clean and fresh as before. The climate is warmer than before.