若（a-1）²与|b+1|的值互为相反数，则a+b=(       )

从某校高三年级中随机抽取一个班，对该班50名学生的高校招生体检表中的视力情况进行统计，其结果的频率分布直方图如图所示，若某高校A专业对视力的要求在0.9以上，则该班学生中能报A专业的人数为（　　）

阅读下列短文，从每小题的三个选项中选出最佳选项。

    It's autumn. It's cool and windy. Charlie is flying a kite in the park. His father is watching(观看).The kite is flying high(高) in the sky. They are happy. Look! The kite is not in the sky now. Where is it? Oh, it's in a tree. Charlie is sad. Charlie jumps and jumps. The tree is tall but he is short. He cannot get(拿到) the kite. Charlie's father is not very tall but he is clever(聪明的). Look, he is on a car. He can get the kite for Charlie. Charlie is happy.

读“中国四大地理区域图”，完成问题．
 
下列四条河流中，最有可能位于丙地区的是（ ）