Connecting main clauses with und, aber, oder and denn

In brief

Use und (and), aber (but), oder (or) and denn (for/because) to join two complete German main clauses. Each clause keeps its usual word order: the conjugated verb is in second position within its own clause. The conjunction does not count as the first position of the second clause.

Form

Main clause + und/aber/oder/denn + main clause; in each clause: first element + conjugated verb + remainder.

Usage

• Use und to add information, aber to show a contrast, and oder to offer an alternative.
• Use denn to give a reason; it introduces another main clause with the conjugated verb in second position.
• Put a comma before aber and denn when they connect clauses. A comma is normally unnecessary before und or oder in these examples.

Examples

• Ich koche heute und mein Bruder deckt den Tisch. — I’m cooking today, and my brother is setting the table.
• Sie hat wenig Zeit, aber sie hilft mir trotzdem. — She doesn’t have much time, but she still helps me.
• Fahren wir mit dem Bus oder gehen wir zu Fuß? — Are we taking the bus or walking?
• Ich bleibe heute zu Hause, denn ich bin müde. — I’m staying home today because I’m tired.

Common mistake

❌ Ich bleibe heute zu Hause, denn bin ich müde.

✅ Ich bleibe heute zu Hause, denn ich bin müde.

After denn, start a normal main clause: ich is the first element and bin is the conjugated verb in second position. Do not invert the subject and verb just because a conjunction comes first.

Remember

After these conjunctions, the second main clause still has its conjugated verb in second position.