晚上太阳下山时，小明面对太阳，请问小明的身后是____。
— How do you like the regulations of our school?
— The regulations are strict with the students and they require that students _______ at least 90% of the lectures.
标准值是指一个国家某数据与世界平均水平之差的标准化数值．读“我国城市化与经济发展水平演变路径”及“城市化与经济发展水平关系图”，完成下题．
