Electro Magnetic Field (EMF) monitoring/interference is one of the most insidious and secretive of all methods used by the agencies.
Electro Magnetic Field (EMF) monitoring/interference is one of the most insidious and secretive of all methods used by the agencies.
电磁场（EMF）监控/干扰是所有被机构运用的方法中其中一个最隐蔽、最秘密。