Our troops are being used up to the last man.
used up 为何不是直接接上宾语，而要加上to？ 这时的to the last man是宾语还是结果？
这个句子是目前进行时的被动语态，句子的主语Troops就是原来主动语态的谓语use up的宾语。介词短语to the last man是介词短语作程度状语，介词to常可用以表示程度。又如：
The bus service has been cut to the bone. 公共汽车服务已经削减到了最低限度。
They were killed to the last man. 他们被赶尽杀绝。
Her dress reached down to her ankles. 她的连衣裙垂至脚踝。