产生错觉的因素是
A．环境因素
B．心理因素
C．意识状态
D．个体因素
E．以上均是
参考答案：E
—Believe it or not, I have met him before.
—No kidding? ________ you've never mentioned it?
A．What for
B．How come
C．How about
D．What if
2，2，3，4，9/2，（）。
A．5
B．11/2
C．6
D．11/3
