Her 1st basis factor B one points up into the right a little bit, and her 2nd vector be two points left and up.

第一个基因子B向右向上一点 第二个向量向左向上两点。

The primary factor, B say the study's authors: U.S. troops are subjected to multiple tours of high-intensity guerrilla warfare and face the constant threat of death or dismemberment from improvised bombs.

这份研究的作者表示，最主要的因素在于--美军参与许多高压且紧张的游击战任务，并不断面临死亡或是被土制炸弹炸断四肢的威胁。