Why does the woman want to buy some plants?

M: Hi, Miss. Freezing cold, isn’t it? What can I do for you?
W: I’d like some plants that can keep the earth fresh.
M: Especially in this cold season when you can’t keep die window open, isn’t it?
W: Absolutely. And something that’s easy to care for and not expensive.
M: OK, Miss. Our shop won’t disappoint you. Look at these plants. They’ve just come in and I bet you like one of them. This is a corn plant. The tall tree can grow more than six feet and it doesn’t need any water or light.
W: Quite striking, isn’t it? What’s that?
M: A palm. It adds a tropical touch to your room. The leaves are perfect for cleaning your air. It has a long life and it’s easy to care for.
W: Oh, this lovely small plant has beautiful white flower. What do you call it?
M: Peace lily. Even the flower isn’t blooming, its dense leaves look great.
W: Perfect. It’s just what I want.
M: Won’t you have a look at Janet Craig and Mother - in - Law’s Tongue? And they’re just as good.
M: No, thanks. The peace lily is OK. The more I see, the less certain I become, you know.