您可以尝试以下操作：

! is_admin() && add_filter( \'the_content\', function( $content )
{
    if( in_the_loop() )   // <-- Target the main loop
    {
        $prepend = \'HERE IS SOME CUSTOM TEXT\'; // <-- Edit your text here
        $content = $prepend . $content;
    } 
    return $content;
}, 9 ); // <-- Choose some priority < 10