My sister and I both go to school at 7:15.Ivan lives on the tenth floor.Alice lives on the sixth floor合并为一句Ivan lives on the tenth floor and Alice lives on the sixth floor.这里因为两个人住的不是同一层，所以中间加个and就可以了。前面因为两个人都是7：15去学校，可以用both合并。希望帮到你。