Students always hesitate when talking about going to countries and cities in French. Should I use à, en, au?
Actually, it's very easy if you know the genre of the country you are going to. Some countries are feminine (La France, La Chine, La Suède) and you must use EN with those. Je vais EN Chine, je vis EN France.
Some countries are masculine, (le Portugal, le Vietnam, le Lesotho) and then you use AU:
Je vais AU portugal, je vis AU Vietnam
As for cities, it's usually "à":
Je vis à Vienne, je vais à Paris, j'étudie à St-Petersbourg, je me suis mariée à Marseille
This rule is only valid...