下图农业生产活动常见于我国的( )
A:东南丘陵
B:内蒙古高原
C:吐鲁番盆地
D:黄土高原
用配方法解方程x2﹣2x﹣5=0时,原方程应变形为( )
Two old men were playing chess in the park with trees ________ shade.