右图中A、D为单质。下列A、B等之间的反应，不能完全符合右图的转化关系的一组是 （ ） A. Na、H2O B. Mg、CO2 C. Al、Fe3O4 D. C、SiO2
如图， ABCD的对角线AC、BD相交于点O，AE=CF. (1)求证：△BOE ≌△DOF ; (2)若BD=EF，连接DE、BF，判断四边形EBFD的形状，无需说明理由.
People the Sailor first became a popular cartoon in the 1930s.The sailor in that cartoon ate lots of spinach to make him strong. People watched him, and they began to buy and eat a lot more spinach
According to an official report on youth violence（暴力）, “The greatest danger to the lives of children is not disease or food shortage, but violence”. Why aren’t students taught to mana
We don’t want to buy a piano,for it so . A.takes up;many rooms B.makes up;much room C.takes in;a large room D.takes up;much room
The flag, the most common symbol of a nation in the modern world, is also one of the most ancient. With a clear symbolic meaning, the flag in the traditional form is still used today to mark buildings
2010年9月以来，海南省遭遇49年来的特大暴雨，导致岛内部分食品价格上涨，如排骨卖到120元/千克，给人民生活带来了不利影响。这一现象说明
在△ABC中，角A，B，C的对边分别是a、b、c，已知且. （I）求角A的大小； （2）若为边上的中线，，，求的面积．
