Complex sentence: The German counter-attack gained some ground against the hills occupied by the Allies its aim was to push the Americans from the hills north of Montélimar and to force the American artillery to move back out of range.
Split into simpler sentences: The German counter-attack gained some ground against the hills occupied by the Allies. Its aim was to push the Americans from the hills north of Montélimar and to force the American artillery to move back out of range.