AbleCommerce Shopping Cart Software

I saw that Ablecommerce 7.0 doesn't limit number of categorizes and products.
So, Can I build a website selling many kinds of products like Electronics, Clothes, Books...?
Does Ablecommerce 7.0 enable developer to construct new function for a specified categorize?
I didn't find any website built by Ablecommerce 7.0 that sell different kind of product. If you can, please show me a website like that?

I'm not sure why you think it would be a problem. You can have any number of categories and any number of products. If you want a different "look" for each product line, you can select a different theme. For example, this site has purchasable paintball products, but also has a paintball museum for out of production products, with a different theme applied to each:
Purchasable:
http://www.directpaintball.com/

Museum:
http://www.directpaintball.com/Paintbal ... C4997.aspx

You can also set your left nav to display categories under a particular category id - if you use categoryid=0, that displays them all, but if you use different category ids, it displays only the links under that main category.

All this narrows down to the same checkout, though.

Thank you for your response.
Now, my site has 20 categories. I want to add a new category, please show me some guide (code or document about Ablecommerce 7.0...) to do that.

You just go to the admin, click Catalog -->Browse. Over at the right there is a link to add a new category. Help docs are located at help.ablecommerce.com.

Thank you.