• 2022-06-06
    中国大学MOOC: http://edu-image.nosdn.127.net/_PhotoUploadUtils_3ba3ed3d-f9cf-4c5a-bfd1-d7e7d6b381f2.png与http://edu-image.nosdn.127.net/_PhotoUploadUtils_59cb357c-e3c1-47cb-9180-6ffafcc8e281.png是异面直线,则必有 ( )