题干
This is ____ pen. It's _____ English pen.
A：a; an
B：a; a
C：an; an
D：an; a
答案(点此获取答案解析）
A
This is ____ pen. It's _____ English pen.
A：a; an
B：a; a
C：an; an
D：an; a
的值域是R，则m的取值范围是
B. 
C. 