题目

 I         to get there before seven tomorrow, so I’ll have to get up early. A  told      B  have told        C  will tell        D  was told 答案： D已知函数,有如下结论①函数f(x)的值域是[-1,1];②函数f(x)的减区间为[1,3];③若存在实数x1、x2、x3、x4,满足x1<x2<x3<x4,且f(x1)=f(x2)=f(x3)=f(x4),则x1+x2<0;④在③的条件下x3+x4=6;⑤若方程f(x)=a有3个解,则<a≤1其中正确的是A. ①②③ B. ③④⑤ C. ②③⑤ D. ①③④