Bad: Sometimes a schema indicates that a data item is optional when some other part of the system downstream fails without the data. Here is an optional element in XML schema.
不好的方法：有时候模式中会指示数据项为可选，但系统中其他的部分却可能因为这部分数据的缺失而失败。
2
You might have to whip out a soldering item and deal with some bad connections.
这时你可能需要一些焊接项目，修复那些坏死的线路连接。
3
Unfortunately, traditional collaborative filtering algorithm does not consider the problem of item's multiple contents and often leads to bad recommendation when item has multiple contents.