题目

Allow others the space to voice their opinions, ______ they are different from yours. A. as though       B. as if                C. unless               D. even though 答案：D（本题满分14分）已知向量，，函数f（x）=·． （1）求函数f（x）的单调递增区间． （2）在△ABC中，分别是角A、B、C的对边，且，求△ABC面积S的最大值．