"Où sommes-nous ?"
Translation:Where are we?
The word sommes is a conjugation of both verbs 'sommer' and 'étre', when you clicked on conjugate to see the table, Duolingo presents both these verbs as 'sommes' is common to both. Perhaps you didn't notice this. Next time, click on the table but look at the top to see if there is other verbs listed- make sure you click on the relevant one to see the correct conjugation.
In this case: 'nous sommes' for 'étre' and and not 'tu sommes' for 'sommer'.