读一读，选择合适的句子补全对话。

A. What can I do? B. It's for Earth Day. C. I can draw some signs on the poster. D. They should stop cutting down trees. E. On Earth Day, people work together to keep the Earth clean and healthy.

David: What are you doing, Simon?

Simon: I'm making a poster.

David: What is Earth Day?

Simon:

David: That's wonderful!

Simon: We can make a poster together. We can tell people to save the Earth.

Simon: Yes! I'm good at drawing.

David: Good idea．Where do we put this poster?

Simon: We can put it in the classroom. Every student can see it on Earth Day.