Hi Qinghan Jiang,

The AP US History course is only shown in the My Courses menu for users located in the U.S.. If you're located outside the U.S. or using a VPN, then this course might not be shown to you. One workaround for this is to use a U.S.-based VPN or manually override your browser's location settings.

Regardless of location, you should still be able to access the course via the direct link: https://www.khanacademy.org/humanities/ap-us-history?lang=en

If you're currently located in the U.S. and are unable to see the course, please submit a support ticket so we can take a closer look.

I hope this helps!