题目

 “Have a nice day!” may be a pleasant gesture or a meaningless expression. When my friend Maxie says “Have a nice day!” with a smile, I know she sincerely cares about what happens to me. I feel loved and secure since another person cares about me and wishes me well. “Have a nice day. Next!” This version(版本) of the expression is spoken by a salesgirl at the supermarket who is rushing me and my groceries out the door. The words come out in the same tone with a fixed procedure. They are spoken at me, not to me. Obviously, the concern for my day and everyone else’s is the孟德尔在豌豆杂交实验中，发现问题和验证假说所采用的实验方法依次是 A．自交、杂交和测交               B．测交、自交和杂交 C．杂交、自交和测交               D．杂交、测交和自交