电火花检漏仪是根据（）原理工作的。
A.欧姆定律
B.电磁感应
C.能量守恒
D.高压放电
参考答案：D
求下列各式中x的值．
（1）4x2=81
（2）8（x-1）3=-27．
Excuse me, but can you tell me ________?
A. where can I get to the library
B. B. how I can get to the library
C. how can I get to the library
D. where I can get to the library
