题目

    As an experienced photojournalist in Nashville, Tennessee, I was hired by USA Today newspaper to photograph a spinal bifida (脊柱畸形) corrective surgical procedure. It was to be performed on a twenty-one week old fetus（胎儿）in uterus（子宫）at Vanderbilt University Medical Center. At that time, in 1999, twenty-one weeks in uterus was the earliest that the surgical team would consider for surgery. The worst possible outcome would be that the surgery would cause premature delivery, and no child born earlier than twenty-three weeks had survived.     The tension c两个角，它们的比是7：3，差为36°，则这两个角的关系是（ ）A. 互余 B. 互补C. 既不互余也不互补 D. 不确定