阅读对话，选择正确的一项。

Two girls are good friends. They are talking.

Lily: Oh, my bag is heavy.

Mary: What's in your bag?

Lily: Look! Ten storybooks, two pencils, one eraser, three Chinese books and four English books.

Mary: Wow! That's really heavy.

Lily: What about your bag?

Mary: Look! A storybook, a pencil, a ruler, an eraser and a maths book.

Lily: Oh, your bag is very light.