<?php

error_reporting(-1);

$text = "so what.      u still dont watch black mesa.i will dowload it  ,but i dont have any time.";
// Для тестов
// $text = 'roses are red,and violets are blue.whatever you do i'll keep it for you.';
// $text = 'привет.есть 2 функции,preg_split и explode ,не понимаю,в чем между ними разница.';

$lines = preg_split("/(?<=\\.)/",$text, -1, PREG_SPLIT_NO_EMPTY);
		/*$result = ucfirst($lines);*/
		print_r($lines);
		
		
function makeFirstLetterUppercase($lines) 
	{
					foreach($lines as $upper)
			{
				$upper = ucfirst($lines);
				print_r($upper);
			}
			print_r($upper);
	}

/* исправляет текст */
function fixText($text) 
	{
		
    
	}
	

$result = fixText($text);
echo "{$result}\n";
makeFirstLetterUppercase($text);