Oh, Thank you so much. I found my problem.
(I entered the codes in functions.php (parent theme not child), then It works!)
Warning: include(/home/hosting_users/keh3084/wp-content/themes/dobp/single-basic.php): failed to open stream: No such file or directory in /home/hosting_users/keh3084/wp-includes/template-loader.php on line 74 Warning: include(): Failed opening ‘/home/hosting_users/keh3084/wp-content/themes/dobp/single-basic.php’ for inclusion (include_path=’.:/usr/local/php53/lib/php’) in /home/hosting_users/keh3084/wp-includes/template-loader.php on line 74
Here is my error messages. What should I do?