题干
— This is my teacher Mr. Black.
—
A：Oh, you are nice.
B：Are you a teacher?
C：Nice to meet you.
D：OK.
答案(点此获取答案解析）
C
— This is my teacher Mr. Black.
—
A：Oh, you are nice.
B：Are you a teacher?
C：Nice to meet you.
D：OK.
、
为实数，则“
”是“
”的 ( )