【新人求助】小白在用eclipse创建第一个安卓项目的时候就出错

[2016-01-26 13:12:46 - appcompat_v7] C:\Users\Administrator\workspace\appcompat_v7\res\values-v21\themes_base.xml:136: error: Error: No resource found that matches the given name: attr 'android:windowElevation'.
[2016-01-26 13:12:46 - appcompat_v7]
[2016-01-26 13:12:46 - appcompat_v7] C:\Users\Administrator\workspace\appcompat_v7\res\values-v21\themes_base.xml:140: error: Error: No resource found that matches the given name: attr 'android:windowElevation'.
[2016-01-26 13:12:46 - appcompat_v7]
还有这个