题干
There is ruler, eraser and some pens in my pencil-box.
A：an; a
B：a; an
C：a; the
D：the; /
答案(点此获取答案解析）
B
There is ruler, eraser and some pens in my pencil-box.
A：an; a
B：a; an
C：a; the
D：the; /
