计算:
(b-2a)2-4a(a-b)。
解:原式=b2-4ab+4a2-4a2+4ab=b2
11. The graduate never expected that his graduation essay would ______ such a heated discussion among scholars.
A.set off
B.set about
C.set out
D.set up
外伤造成的眼球破裂,眼内容大量脱出使眼球变软,摘除中可能的困难有()、()。