教师用红色钢笔批改作业利用的是知觉的哪一个特性？ (     )

试卷相关题目

SQL Error: select id,body,options from ***_enewstiku where sourceid='26671' and id < 2220247 and id<>'2220247' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='26671' and id > 2220247 and id<>'2220247' order by id asc limit 5