2. it (any noun considered masculine in French) 3. it (referring to weather) example: Il va pleuvoir. ( It's going to rain).
1. she 2. it (any feminine noun).
1. one ( impersonal "you"/any person): Qu’est-ce qu’on peut dire? (What can one say?) On ne sait jamais. (You never know/One never knows).
2. we (this use is VERY common) : On est en retard. (We're late.) On va partir. ( We're going to leave). Qu’est-ce qu’on va faire? ( What shall we do?)
3. you: On s’amuse bien? (Are you having fun?)
4. they/ the authorities/ the people in charge/ the governmet: On va construire un pont. (They're going to build a bridge).
5. someone: On m’a dit...( I was told/someone told me/I've been told)
6. they (people): Que pensera-t-on? (What will people think?)
Would you like more details? ;)