"He used to see his girlfriend only on Sundays."

Translation: Il ne voyait sa petite amie que le dimanche.

[zed5000]

How do you determine what goes inside the 'ne....que'?

[linguaphile16]

The thing that it is limited to comes just after the que. If you said "Il ne voyait que sa petite amie le dimanche", you would be saying that he saw only his girlfriend (and not anyone else) on Sundays. So it is kind of like English, where "only" comes right before what it is limited to. It is just confusing because most ne... phrases only encompass the verb and any preceding object pronouns. This one is different.

[zed5000]

thanks so much that's really helpful...now I hope i can remember it in future - it was drivng me crazy not being able to figure out the rule!

[Sucy-en-Brie94]

Il ne voyait sa copine que le dimanche. Accepted :)

[Mister_Matthew]

French is stupid! So am I!