根据题意得:
(m2-2m)-(m2+m-2)
=m2-2m-m2-m+2
=-3m+2.
故答案为:-3m+2.
—_____ you _____ the window?
—Yes, I am.[ ]
A. Is, cleaning
B. Do, cleaning
C. Are, cleaning
D. Do, clean
CATIA的零件档案建立2D图的时候,所显示的投影法为第一角法,如何修改为第三角法?