Die Intelligenz von Hunden wurde lange unterschätzt.
The intelligence of dogs was underestimated for a long time.
Ein Test kann die Intelligenz nicht vollständig messen.
A test cannot measure intelligence completely.
Note
The article is part of the word: die Intelligenz. That way you learn the gender with it.
Remember die Intelligenz for good. ripiti brings the word back just before you forget it, with these sentences. Free, no account needed, works offline.