问PHP如何查找从某个日期开始经过的时间？

EN

function getTimeSince($eventTime)
{
    $totaldelay = time() - strtotime($eventTime);
    if($totaldelay <= 0)
    {
        return '';
    }
    else
    {
        $first = '';
        $marker = 0;
        if($years=floor($totaldelay/31536000))
        {
            $totaldelay = $totaldelay % 31536000;
            $plural = '';
            if ($years > 1) $plural='s';
            $interval = $years." year".$plural;
            $timesince = $timesince.$first.$interval;
            if ($marker) return $timesince;
            $marker = 1;
            $first = ", ";
        }
        if($months=floor($totaldelay/2628000))
        {
            $totaldelay = $totaldelay % 2628000;
            $plural = '';
            if ($months > 1) $plural='s';
            $interval = $months." month".$plural;
            $timesince = $timesince.$first.$interval;
            if ($marker) return $timesince;
            $marker = 1;
            $first = ", ";
        }
        if($days=floor($totaldelay/86400))
        {
            $totaldelay = $totaldelay % 86400;
            $plural = '';
            if ($days > 1) $plural='s';
            $interval = $days." day".$plural;
            $timesince = $timesince.$first.$interval;
            if ($marker) return $timesince;
            $marker = 1;
            $first = ", ";
        }
        if ($marker) return $timesince;
        if($hours=floor($totaldelay/3600))
        {
            $totaldelay = $totaldelay % 3600;
            $plural = '';
            if ($hours > 1) $plural='s';
            $interval = $hours." hour".$plural;
            $timesince = $timesince.$first.$interval;
            if ($marker) return $timesince;
            $marker = 1;
            $first = ", ";

        }
        if($minutes=floor($totaldelay/60))
        {
            $totaldelay = $totaldelay % 60;
            $plural = '';
            if ($minutes > 1) $plural='s';
            $interval = $minutes." minute".$plural;
            $timesince = $timesince.$first.$interval;
            if ($marker) return $timesince;
            $first = ", ";
        }
        if($seconds=floor($totaldelay/1))
        {
            $totaldelay = $totaldelay % 1;
            $plural = '';
            if ($seconds > 1) $plural='s';
            $interval = $seconds." second".$plural;
            $timesince = $timesince.$first.$interval;
        }        
        return $timesince;

    }
}