题干
The Internet brings much convenience to us. It allows us to order goods online, ______ us one trip after another.
A：sharing
B：sparing
C：reducing
D：affording
答案(点此获取答案解析）
B
的圆形匀强磁场区域中．线框顶点与右侧圆中心重合，线框底边中点与左侧圆中心重合．磁感应强度