【单选题】We were prepared to make some concession on ________ details, but we would not compromise on fundamentals.
【简答题】已知向量 、 的夹角为 ,且 , ,则向量 与向量 的夹角等于 .
【简答题】已知等腰三角形一腰上的高与另一腰的夹角为40 °,则其顶角的度数为 .
【单选题】So carefully ____ the performance that it went smoothly in the competition. [ ]