A:结束了春秋战国以来的分裂割据局面,完成统一
B:创立了一套封建专制主义的中央集权制度
C:推行郡县制,在我国历史上影响深远
D:统一了货币、度量衡和文字
Many students take the school bus to school every day. Parents think taking the school bus is usually safe (安全的), but sometimes it is dangerous. Some students don't keep the school bus rules. What are the school bus rules?
Arrive at the bus station early.
Wait for (等候) the school bus at the bus station.
Don't run at the bus station.
Don't walk or fight on the bus.
Don't get off (下车) the bus when it goes.
火箭是用液态氢作为燃料的,这是因为液态氢具有的优点是( )
下列有关文学常识和名著阅读的表述,不正确的一项是( )
在△ABC中,a、b、c分别为角A、B、C所对应的三角形的边长,若4aBC→+2bCA→+3cAB→=0→,则cosB=( )