The length of the war is one of the biggest unknowns.战争要持续多久是最大的未知数之一。There are many unknowns in science.科学上还有许多未知之处.It was like a single equation with two unknowns.这挺像两个未知数组成了个简单方程....
The silence lengthened as Thorne unnecessarily shuffled some papers.索恩整理着一些本无须整理的文件，沉默还在延续。They have pulled out patients' teeth unnecessarily.他们毫无必要地拔掉了病人的牙。I don't want to invade your private life unnecessaril...