分支语句：
1. if (expr) statement || else || else if / elseif
2. switch () || case || default
loop:
1. while (expr) statement || do while (expr)
2. for (expr1 ; expr2 ; expr3) statement || foreach ($arr as $value) statement || foreach ($arr as $key => $value) statement
引入：
1. require requre_once
2. include include_once
控制：
1. break
2. continue for loop stmt
3. return $value
4. goto (namely:)
声明：
1. declare --->>> encoding || ticks || strict_types
其他语法形式：
1. if(): endif; || while(): endwhile; || switch (): endswitch; || for(): endfor; || foreach(): endforeach;
