| A．They are forests. | B．They are trees. |
| C．They are ponds. | D．They are oceans. |
| A．It is on 12th May. | B．It is on 12th March. |
| C．It is on 20th March. | D．It is on 13th May. |
| A．Why we should plant more trees? |
| B．What should we do to help the Earth? |
| C．What should we do to protect the air? |
| D．When should we protect the Earth? |
| A．used; to make | B．used; made |
| C．use; to make | D．use; made |
| A．clean | B．cool | C．hot | D．beautiful |
| A．with | B．of | C．from | D．on |
| A．keep; live | B．keeps; alive | C．keep; alive | D．keep; live |
| A．slower | B．slow | C．slowly | D．slowest |
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