parse errors:
'md-card' is not a known element:
1. If 'md-card' is an Angular component,then verify that it is part of this module.
2. If 'md-card' is a Web Component then add 'CUSTOM_ELEMENTS_SCHEMA' to the '@NgModule.schemas' of this component to suppress this message. ("<h2>Nothing to show</h2>
[ERROR ->]<md-card>Simple card</md-card>
"): ng:///AppAccessModule/SPLoginComponent.html@1:0
    at SyntaxError

当我尝试在一个文件夹中嵌套两次的组件中使用材料时

这些是我的结构：

-----Components(folder)
  -------Auth(folder)
  --------Login(component1)
  --------Signup(component2)

但如果我下一次喜欢这样：

-------Auth(folder)
  --------Login(component 1)
  --------Signup(component2)

我没有任何问题我该怎么做才能解决这个问题？谢谢