Why is the letter E so important?

问题描述:

Why is the letter E so important?
顺便也帮我写 When do people have two mouths?
What is full when it 's used and empty when it'sat rest
When do people have two mouths?

EYE
What is full when it 's used and empty when it'sat rest --lung(肺)
When do people have two mouths?--