Yesterday morning he got up earlier than________ , for it was not a(n)________day.
A:common; usual
B:usual; ordinary
C:usual; normal
D:common; ordinary
若a、b、c为实数,且a+b+c=1,则a2+b2+c2的最小值为____
下图中的中外两幅名画的共同点是( )