题目

Your MP4 is quite cheap. Where did you buy _________? I want to buy _________, too. A. one; one        B. it; it          C. it; one         D. one; it 答案：C5．给出六个多项式：①x2+y2；②-x2+y2；③x2+2xy+y2；④x4-1；⑤x（x+1）-2（x+1）；⑥m2-mn+$\frac{1}{4}$n2．其中，能够分解因式的是②③④⑤⑥ （填上序号）．