Questions & Answers about Nous voyons la lune.
Because the subject is nous (we), and French verbs change form depending on the subject.
The verb here is voir (to see). In the present tense:
- je vois
- tu vois
- il / elle / on voit
- nous voyons
- vous voyez
- ils / elles voient
So with nous, you need voyons.
One useful thing to notice is that nous forms often help show the stem clearly in French verbs.
Voyons is pronounced roughly like vwah-yon, but with a nasal ending.
More exactly:
- voy- sounds like vwah-y
- -ons sounds like on in French, with a nasal vowel
- the final s is silent
So the whole word is approximately /vwajɔ̃/.
A native English speaker should also notice that the y in voyons is pronounced; it is not silent.