急急急！！！安装vs2015所遇到的问题，

[weixin_38055995]

 我用win8系统下载安装vs2015，遇到安装已完成，但并非所有功能均已正确安装，                              
                            Android SDK 安装(API 级别 22) : The following package(s) were not downloaded: build-tools-22.0.1 android-22 . Please check your internet connection and try again.
Android SDK 安装(API 级别 23) : The following package(s) were not downloaded: build-tools-23.0.1 android-23 . Please check your internet connection and try again.
Android SDK 设置(API 级别 19 和 21) : The following package(s) were not downloaded: platform-tools extra-android-m2repository build-tools-19.1.0 build-tools-21.1.2
android-19 android-21 sys-img-armeabi-v7a-android-19 sys-img-x86-android-19 addon-google_apis-google-19 . Please check your internet connection and try again.
屏幕上显示这些问题，求大神帮助，我该怎么办？