当x=5-1时，
x2+5x-6
=（5-1）2+5（5-1）-6
=6-25+55-5-6
=35-5．
社会保险基金
________ for the fact that she broke her leg, she might have passed the exam.
A．Hadn’t it been
B．Had it not been
C．Was it not
D．Were it not
