因式分4x4-4x3+x2=______．
原式=x2（（4x2-x+1）．
故答案为：x2（（4x2-x+1）．
已知x-y=2，则x2-2xy+y2=（ ）。
Are ______ Kate’s ______? [ ]
A. this, book
B. that, book
C. these, books
D. those, book
