精密冲裁比采用其它的加工方法，其成本显著降低，并且（）程度高。
A.显著增高
B.自动化
C.基本相同
D.略有增高
参考答案：B
_____ the burden of carrying heavy school bags, some schools introduced iBooks a few weeks ago. [ ]
A . Eliminating
B. Eliminated
C. To eliminate
D. Having eliminated
母联兼旁路开关代替线路开关或变压器开关运行时，其保护须按所代开关的保护定值更改后方可代替运行。
