关于x的一元二次方程-x2+（2m+1）x+1-m2=0无实数根，则m的取值范围是（ ）
m＜-
The project is based on an agreement, one of ________ purposes is to ensure that the project can be
accomplished before the deadline. [ ]
A. whose
B. which
C. its
D. what
求图所示刚架A、B两截面的相对转角，虚设广义单位荷载应为（）
A.A
B.B
C.C
D.D
