题目

Some boys are sometimes afraid of ____(make) mistakes in the test. 答案：【答案】making【解析】句意：有些男孩有时害怕在考试中犯错误。固定搭配：be afraid of doing sth“害怕做某事”，动名词作宾语，故填making。已知函数f（x）=（a+1）lnx+ax2+1．（Ⅰ）讨论函数f（x）的单调性；（Ⅱ）设a≤-2，证明：对任意x1，x2∈（0，+∞），|f（x1）-f（x2）|≥4|x1-x2|．