Where the English are perfectly happy with only one definite article (the), the Dutch have to choose between two articles: 'de' and 'het'. How inconvenient, indeed. In the old days, the Dutch had even three definite articles, just like in German. The message is that it could have been worse.
So what is the point of using two different articles? Frankly, there is no point. Nor is there a clear-cut rule for determining which nouns get 'het' as an article and which ones get 'de'. Unfortunately, non-native speakers just have to put up with it and learn the de and het nouns by heart. On the other hand, we are only dealing with tiny little, one-syllable words. If you mumble them a bit unintelligibly, no one might notice your mistakes.
| .
| de-nouns
| het-nouns
|
| singular
| de
de man
(the man)
| het
het huis
(the house)
|
| plural
| de
de mannen
(the men)
| de
de huizen
(the houses)
|
In those old days, each gender had its own article: masculine, feminine, and neuter. In modern Dutch, the distinction between feminine and masculine articles has disappeared: They are both 'de'. Because of the emancipation of feminine and masculine articles, there is no point talking about the gender of articles anymore. Instead, we simply talk about de and het nouns, where 'het' is of course the article of a neuter noun.
As you can see, plural nouns always take 'de'.
Questions? 
