分类：教育/科学-学习帮助
问题：单项选择22.thebrownshavea_________da 
22.the browns have a _________ daughter.
a.three-years-old b.eight-year-old c.three-year-old d.seven-years-old
回答：c.three-year-old 
首先用了连字符号，那么名词用单数，只有b c 符合
因为前面了a   _________ daughter,所以排除了b
如果用b，前面用an eight-year-old