List two ways in which governments works together to solve their problems?

hmm.. your question is a bit uncleear, but I'd say an example could be when two countries build a bridge over a river (border) in order to improve the communication. in such case the two of them need to invest some money in it and cooperate. another one would be maybe when a European country sends food to another country, eg. in Asia which was hit by a natural catastrophy. in this case one gives helps and the other one receives it. is that enough?