Toward - towards

What about towards and toward? One of my own students was worried that there might be similar pitfalls in store for her when using these prepositions. Well, I can re-assure all of you that these prepositions can be used quite interchangeably and that there is no difference in meaning. The only slight difference in usage is that toward is perhaps more characteristic of American English and towards more usual in British English. Toward or towards means 'in the direction of':

• 'Can you see that light over there?' 'I think it’s coming towards us.'
• 'There are always more mosquitoes in the air toward evening. Have you noticed?'