如果方程（x-a）2=b有实数解，那么b的取值范围是______．
由方程（x-a）2=b有实数解，
可得b≥0．
故答案为：b≥0
Jack always sleeps late on Sundays. I am sure he _______ when we get home.
A．is still sleeping
B．is to be sleeping
C．will still be sleeping
D．will have been sleeping
ISBP是对《UCP600》的修订。( )
