Ⅱ 单项选择 (每小题1分，共18分)
从A、B、C、D四个选项中选出可以填入空白处的最佳答案，并把答题卡上对应题目的答案标号涂黑。
( )21. My mom is ____ teacher. She’s ____ English teacher.
A. a; an B. a; a C. an; a D. an; an
( )22. —____ is Mary？—She is five.
A. Who B. How C. Where D. How old
( )23. —What ____ is Jane in?—She is in ____ Six.
A. Class; Class B. Class; class C. class; class D. class; Class
