关于x的方程(a2-a-2)x2+ax+b=0是一元二次方程的条件是[ ]
A.a≠-1
B.a≠2
C.a≠-1或a≠-2
D.a≠-1且a≠2
答案:D
---How do you find James Cameron's 3D version of Titanic?
---Fantastic! It can't be _______ and has brought us a wonderful experience.
A.more impressive
B.as impressive
C.most impressive
D.so impressive
简答造林整地的主要技术规格。