5.by/through the back door偷偷摸摸地；不光明正大地
The government would not allow anyone to sneak in by the back door and seize power by force.政府不会允许任何人偷偷混进来并用武力攫取政权
They claim the Government is privatizing dentistry through the back door.他们声称政府正在通过不正当手段将牙医业私有化。