It's six forty in the morning. The children are coming into the classroom.

    A girl is opening the windows. Some are laughing and talking. Some are listening to them. Some are reading books. Some are doing their homework.

Miss Lin is standing behind the teacher's desk. She is writing on the blackboard. Sue and Anna are wearing their new dresses today. Ann is cleaning her desk. Mike is helping her. They all look happy.

    What are Bill and Bob doing? Oh, dear! They are still playing basketball.

某公司专为黑人研制的化妆品在下列地区中最适合的销售地区是（　　）

若f：A→B能构成映射，则下列说法正确的有（　　）

（1）A中的任意一元素在B中都必须有像且唯一；

（2）A中的多个元素可以在B中有相同的像；

（3）B中的多个元素可以在A中有相同的原像；

（4）像的集合就是集合B．

如图所示是银杏树上结的“白果”，对白果的描述正确的是（    ）