Der Vertrag ist lang.

to be

Breakdown of Der Vertrag ist lang.

• lang: long
• der Vertrag: the contract

Questions & Answers about Der Vertrag ist lang.

Why is the sentence using der Vertrag instead of die or das?

In German every noun has a grammatical gender: masculine, feminine, or neuter. Vertrag (contract) is a masculine noun, so it takes the masculine definite article der in the nominative case.

Why is Vertrag in the nominative case here?

Because Vertrag is the subject of the sentence (it’s what the sentence is about). In German, the subject of a clause is in the nominative case.

Why is the adjective lang not inflected (no ending like lange or langer)?

This is a predicative adjective: it follows a linking verb (“sein” → ist) and describes the subject. Predicative adjectives in German do not receive endings, so you simply say lang.

How would I say “The contracts are long” in German?

You’d pluralize both noun and verb:
Die Verträge sind lang.

How do I form a question: “Is the contract long?”

Invert the subject and verb, as German questions do:
Ist der Vertrag lang?

What if I want to use an indefinite article (“A contract is long”)?

Replace der with ein (masculine nominative indefinite article):
Ein Vertrag ist lang.

Can I replace lang with a synonym for “long” or “lengthy”?

Yes. You could use umfassend or ausgedehnt, for example:
Der Vertrag ist umfassend.
Here again the predicative adjective remains uninflected.

How would I refer back to “der Vertrag” with a pronoun?

Use the masculine nominative pronoun er:
Der Vertrag ist lang. Er enthält viele Details.

What changes in word order if I want to emphasize lang?

You can front the adjective phrase for emphasis, then follow with verb-second and subject:
Lang ist der Vertrag.
This is stylistically marked but perfectly correct.