请教几个语法题

题目

请教几个语法题
1.Their friendship dating back to childhood is true.
其中dating back to childhood 在句子当中做什么成分?请举一个类似的例子.
2.E-shopping,when properly done,can save us a lot of time and money.
其中when properly done在句子当中做什么成分?请举一个类似的例子.

答案

1、dating back to childhood在句子中做定语,修饰“their friendship"类似的还有：Their cooperation built on the basis of faith will be successful.这项建立在信任基础上的合作会取得成功.2、when properly done...