"The oranges have sugar."
Translation:Die Orangen haben Zucker.
Whenever you're wondering how to conjugate something, mentally change the noun or proper noun to a pronoun.
Example: "The man has an apple."
Becomes: "He has an apple"
Conjugation: "He" would fall under er/sie/es as "er." Therefore, you'd use the "-t" ending.
Answer: "Der Mann hat einen Apfel"
Let's do another.
Example: "The apples have sugar."
Becomes: "They have sugar"
Conjugation: The "they" form of "sie" gets the "-en" ending.
Answer: "Die Äpfel haben Zucker"
Can you say that something "has" sugar in German when it "contains" sugar? You can't really say "Oranges have sugar" in English. You would have to specify "where" that sugar is (the oranges have sugar in them / on top of them / et cetera) or say that they are made out of sugar.