They just extend the base model classes.

它们只是扩展了基本模型类。

youdao

The base model of the H-P has a 22-inch screen.

而惠普基准机型的屏幕则有22英寸。

youdao

One of the model files, known as the base model, represents the database before the change.

其中一个模型文件（称作基础模型） 表示更改之前的数据库。

youdao

So you sort of have a zero-base budgeting model of, "If we were a start-up, what would we do? How would we organize to deliver value to the customers?"

所以得有一个零基础预算模式，如果我们从头开始，我们该做什么,我们如何组织以带给客户价值“

斯坦福公开课 - 戴尔CEO-Michael.Dell谈创业和发展课程节选

The base model Edge holds 64GB of content in a speedy solid state drive (128GB in the Pro model, upgradeable to 256GB).

ENGADGET: Hands-on with Razer's Edge, a $999 gaming tablet / home console

The base model even has a fare meter included in its dashboard.

FORBES: A Foothold Market -- In Rickshaws

Maybe you should temper your storage expectations a bit, as the base model actually only allots 23GB of that space for use.

ENGADGET: 128GB Surface Pro ships with 83GB free, 64GB has only 23GB