The scientist don't exactly know when the universe but they are still studying it.
A:come true
B:come about
C:came into being
D:come out
米勒首创的化学进化模拟实验从理论上证明下列哪项是可能的( )
若向量a→与b→不共线,a→·b→≠0,且c→=a→-a→·a→a→·b→b→,则向量a→与c→的夹角为( )
关于电流,下列说法正确的是( )