罗马教廷是以（）为首的天主教领导机构。
A.祭司
B.教皇
C.首相
参考答案：B
The system has been designed to give students quick and easy _________to the digital resources
of the library.[ ]
A. access
B. passage
C. way
D. approach
什么叫做过载？什么叫做低电压或电压过低？
