Fatal error: Uncaught Error: Call to undefined function twentyfifteen_post_thumbnail() in /home/xb494747/chuo.ac.jp/public_html/glc/wp-content/themes/glc/content-page.php:14
Stack trace:
#0 /home/xb494747/chuo.ac.jp/public_html/glc/wp-includes/template.php(725): require()
#1 /home/xb494747/chuo.ac.jp/public_html/glc/wp-includes/template.php(672): load_template('/home/xb494747/...', false)
#2 /home/xb494747/chuo.ac.jp/public_html/glc/wp-includes/general-template.php(168): locate_template(Array, true, false)
#3 /home/xb494747/chuo.ac.jp/public_html/glc/wp-content/themes/glc/page.php(21): get_template_part('content', 'page')
#4 /home/xb494747/chuo.ac.jp/public_html/glc/wp-includes/template-loader.php(106): include('/home/xb494747/...')
#5 /home/xb494747/chuo.ac.jp/public_html/glc/wp-blog-header.php(19): require_once('/home/xb494747/...')
#6 /home/xb494747/chuo.ac.jp/public_html/glc/index.php(17): require('/home/xb494747/...')
#7 {main}
thrown in /home/xb494747/chuo.ac.jp/public_html/glc/wp-content/themes/glc/content-page.php on line 14