framework/helpers/BaseInflector.php
public static function sentence(array $words, $twoWordsConnector = null, $lastWordConnector = null, $connector = ', ')
    {
        if ($twoWordsConnector === null) {
            $twoWordsConnector = Yii::t('yii', ' and ');
        }
        if ($lastWordConnector === null) {
            $lastWordConnector = $twoWordsConnector;
        }
        switch (count($words)) {
            case 0:
                return '';
            case 1:
                return reset($words);
            case 2:
                return implode($twoWordsConnector, $words);
            default:
                return implode($connector, array_slice($words, 0, -1)) . $lastWordConnector . end($words);
        }
    }
public static function sentence(array $words, $twoWordsConnector = null, $lastWordConnector = null, $connector = ', ')
    {
        if ($twoWordsConnector === null) {
            $twoWordsConnector = Yii::t('yii', ' and ');
        }
        if ($lastWordConnector === null) {
            $lastWordConnector = $twoWordsConnector;
        }
        switch (count($words)) {
            case 0:
                return '';
            case 1:
                return reset($words);
            case 2:
                return implode($twoWordsConnector, $words);
            default:
                return implode($connector, array_slice($words, 0, -1)) . $lastWordConnector . end($words);
        }
    }
Converts a list of words into a sentence.

Special treatment is done for the last few words. For example,

```php
$words = ['Spain', 'France'];
echo Inflector::sentence($words);
// output: Spain and France

$words = ['Spain', 'France', 'Italy'];
echo Inflector::sentence($words);
// output: Spain, France and Italy

$words = ['Spain', 'France', 'Italy'];
echo Inflector::sentence($words, ' & ');
// output: Spain, France & Italy
```

@param array $words the words to be converted into an string
@param string $twoWordsConnector the string connecting words when there are only two
@param string $lastWordConnector the string connecting the last two words. If this is null, it will
take the value of `$twoWordsConnector`.
@param string $connector the string connecting words other than those connected by
$lastWordConnector and $twoWordsConnector
@return string the generated sentence
@since 2.0.1