Revenir means to return to where the speaker is: "to come back." Thomas va revenir en France. Thomas is going to come back to France (where the speaker is). Retourner means to return somewhere that the speaker is not: "to go back." Note that retourner can also be a transitive verb. Thomas va retourner en France. Thomas is going to return to France (speaker is not in France). 也就是说，revenir和retourner的差别在于说话的人在哪儿。 如果THOMAS要回法国的话，说话的人在法国的话，要用revenir,但说话的人不在法国的话，用retourner