题干
—I want you to be my girlfriend, Sara.
—___! I have somebody in my mind already.
A：You bet
B：You're kidding
C：Come on
D：As if
答案(点此获取答案解析）
B
—I want you to be my girlfriend, Sara.
—___! I have somebody in my mind already.
A：You bet
B：You're kidding
C：Come on
D：As if
确定的等差数列
中，当
时，序号
等于
