题目

Our school          for nearly 10 years, we will celebrate its birthday soon.       A. was opened   B. has been opened   C. has been open   D. was open     答案：C将1、4、6、7、8这五个数分别填在方框里，写成□□□×□□时乘积最大，是 ；将2、3、5、9、0这五个数分别填在方框里，写成□□□×□□时乘积最小，是 ．