问题
Do you know that is _____ grandmother.
A:a 80-year-old
B:80 -years-old
C:an 80-year-old
D:an 80-year-old D80 –year-old
B:80 -years-old
C:an 80-year-old
D:an 80-year-old D80 –year-old
正确答案是：
