How and When to Use the French Preposition "Sur"

The French preposition sur, one of the most common in the French language, usually means "on," but it has a few other meanings as well depending on what it's used with. Here they are.

Location

un livre sur la table > a book on the table
sur ma route > on my way
sur la photo > in the photograph
sur le stade / le marché > at the stadium / market
sur la chaussée, le boulevard, l'avenue > in the road, boulevard, avenue
Il neige sur tout le Canada. > It's snowing all over Canada.

Direction

tourner sur la gauche > to turn to the left
revenir sur Paris > to return to Paris

Approximate time

arriver sur les six heures > to arrive around 6 o'clock
Elle va sur ses 50 ans. > She's going on 50 (years old).
sur une période d'un an > over a period / the course of a year

Proportion/Ratio

trois fois sur quatre > three times out of four
un enfant sur cinq > one child in five
une semaine sur deux > every other week

Subject/Topic

un article sur les roses > an article on roses
une causerie sur l'égalité > a talk on/about equality

After Some Verbs Followed by an Indirect Object

Sur is also required after certain French verbs and phrases that are followed by an indirect object. Note that there is sometimes no equivalent preposition in English but the French usage is idiomatic. Such verbs and phrase include:

acheter quelque chose sur le marché > to buy something at the market
appuyer sur (le bouton) > to press (the button)
appuyer sur (le mur) > to lean (on the wall)
arriver sur (midi) > to arrive at around (noon)
compter sur > to count on
concentrer sur > to concentrate on
copier sur quelqu'un > to copy from someone
croire quelqu'un sur parole > to take someone's word, to take someone at his word
diriger son attention sur > to direct one's attention to
donner sur > to overlook, open onto
écrire sur > to write about
s'endormir sur (un livre, son travail) > to fall asleep (over a book, at work)
s'étendre sur > to spread out over
fermer la porte sur (vous, lui) > to close the door behind (you, him)
interroger quelqu'un sur quelque chose > to question someone about something
se jeter sur quelqu'un > to throw oneself upon someone
loucher sur > to ogle
prendre modèle sur quelqu'un > to model oneself on someone
questionner quelqu'un sur quelque chose > to question someone about something
réfléchir sur > to think about, reflect upon