钻探设备往往伴随着钻探工艺的发展而变化。
参考答案:对
已知a+b-2=0,则代数式(a2-b2)2-8(a2+b2)的值为( )
A.-22
B.-20
C.-18
D.-16
What an unforgettable experience! I’ll write it down ______it is till fresh in my memory.
A. before
B.so that
C.while
D.until