——Jack , you look tired today. What’s wrong?——I was ____busy_______ I didn't go to bed until midnight yesterday.
如果m2﹣m=1,求代数式(m﹣1)2+(m+1)(m﹣1)+2015的值.
珠江三角洲地区现已成为当今世界最大的什么生产基地( )