Complete the dialogue using prepositions from the box-after-at-by-during-for-in-until-in. scientist: well, the company first had the idea ( 1990. we wanted to find a solution to the problem of global warming, and ( march the president offered a prize to the team that came up with the best idea. he gave us six months. ( six months , my team tried several things. ( first we didn't have many ideas, but then we worked on the idea ( six weeks ( we realized that someone else had built it! ( we decided on the idea of the balloons. ( the end of the fourth month we had a good plan. we had been waiting ( the president's decision and finally ( november 7 we found out we had won.
