My sister and I both go to school at 7:15.Ivan lives on the tenth floor.Alice lives on the sixth floor合并為一句Ivan lives on the tenth floor and Alice lives on the sixth floor.這里因為兩個人住的不是同一層，所以中間加個and就可以了。前面因為兩個人都是7：15去學校，可以用both合并。希望幫到你。