A:晶体熔点由低到高:CF4<CCl4<CBr4<CI4
B:硬度由大到小:金刚石>碳化硅>晶体硅
C:熔点由高到低:Na>Mg>Al
D:晶格能由大到小: NaF> NaCl> NaBr>NaI
河蚌的运动器官是( )
— What's it in the bottle?
— It is full of water.
关于经纬线的说法,正确的是( )