A:P4和NO2都是共价化合物
B:CCl4和NH3都是以极性键结合的极性分子
C:在CaO和SiO2晶体中都不存在单个小分子
D:甲烷是对称平面结构,是非极性分子
如果∠1与∠2互补,∠2与∠3互余,则∠1与∠3的关系是( )
西晋卫恒曾指出:“隶书者,篆之捷也。”下列汉字“解”的演变中体现出这一认识的阶段是( )
The Monkey King is a popular cartoon character and he always the hearts of young people.
He _______ an English club last year and has improved his English a lot.