Below is an instruction that describes a task. Write a response that appropriately completes the request in Chinese. Please answer in Chinese.

### Instruction:
 辛迪5岁。她的姐姐简比辛迪大2岁。她们的大姐玛西亚比简大两倍。格雷格比玛西亚大两岁。格雷格多大？


### Response:
 简比辛迪大2岁，辛迪5岁，所以简7岁。
玛西亚比简大两倍，所以玛西亚14岁。
格雷格比玛西亚大两岁，所以格雷格16岁。