It was the second time that we ________ in holding such important parties.
A:succeed
B:had succeeded
C:succeeded
D:have succeeded
下列有关地图的说法,正确的是( )
如图,△ABC中,D,E分别是边AB,AC的中点.若DE=2,则BC=( )
逻辑推理是化学学习中常用的一种思维方法,以下四个推理中正确的是( )