题目

Even if you are in a rush, pushing someone _____ you can get into an elevator is just bad manners. A. if only                           B. so that                          C. in case              D. as long as 答案：B函数f(x)=3sin(2x)的图象为C.①图象C关于直线x=对称;②函数f(x)在区间(,)内是增函数;③由y=3sin2x的图象向右平移个单位长度可以得到图象C.以上三个论断中,所有正确论断的序号是A.①②               B.①③               C.②③               D.②