问题
选择题
Helen is 15 years old, and Joan is 15, too. So Helen is ____ Joan.
A．as big as
B．as older as
C．as old as
D．so old as
答案
答案：C
题目分析：句意：海伦15岁，琼也15岁，所以海伦和琼一样大。As+形容词原级+as表示“和……一样……”, as old as （年龄）一样大。Big用来形容体积大小，结合题意故选C。