presentation layer的用法和样例：
例句
- The recommended approach is to separate the data access logic from the presentation layer.
建议的方法是将数据访问逻辑与表示层分离。 - They do format the screen and accept keystrokes,but they can't handle other aspects of presentation logic,such as screen sequencing and data validation.
它们的确编排了屏幕显示格式，并接收敲键输入，但它们不能处理表示层其它的逻辑操作，如屏幕显示时序排列和数据验证等。
