input: Generate an approximately fifteen-word sentence that describes all this data: Greece, leader, Alexis Tsipras

sentence: The leader of Greece is Alexis Tsipras.

input: Generate an approximately fifteen-word sentence that describes all this data: Atlas II, manufacturer, Lockheed Martin

sentence: Lockheed Martin is the manufacturer of the Atlas II.

input: Generate an approximately fifteen-word sentence that describes all this data: AEK Athens F.C., league, Superleague Greece; Superleague Greece, champions, Olympiacos F.C.; AEK Athens F.C., ground, Athens

sentence:
AEK Athens FC whose grounds are in Athens compete in the Superleague Greece, the champion of which is Olympiacos F.C.