这是什么情况？start出错？

C:\Windows\system32>adb shell am start

Exception occurred while executing 'start':
java.lang.IllegalArgumentException: No intent supplied
at android.content.Intent.parseCommandArgs(Intent.java:7798)
at com.android.server.am.ActivityManagerShellCommand.makeIntent(ActivityManagerShellCommand.java:349)
at com.android.server.am.ActivityManagerShellCommand.runStartActivity(ActivityManagerShellCommand.java:446)
at com.android.server.am.ActivityManagerShellCommand.onCommand(ActivityManagerShellCommand.java:185)
at android.os.BasicShellCommandHandler.exec(BasicShellCommandHandler.java:98)
at android.os.ShellCommand.exec(ShellCommand.java:44)
at com.android.server.am.ActivityManagerService.onShellCommand(ActivityManagerService.java:11161)
at android.os.Binder.shellCommand(Binder.java:935)
at android.os.Binder.onTransact(Binder.java:819)
at android.app.IActivityManager$Stub.onTransact(IActivityManager.java:5331)
at com.android.server.am.ActivityManagerService.onTransact(ActivityManagerService.java:3150)
at android.os.Binder.execTransactInternal(Binder.java:1165)
at android.os.Binder.execTransact(Binder.java:1129)

你的指令用错了
命令格式为：

adb shell am start -n package/launch_activity

示例：
打开设置App命令：

adb shell am start -n com.android.settings/com.android.settings.Settings