A:CH4和—CH3中都存在4对共价键
B:CH4发生取代反应,产物中一定存在—CH3
C:—CH3的电子式为
D:0.5 mol —CH3含有4.5 mol电子
(____) What does your mother do?
(____) Oh, great!
(____) She's a nurse.
(____) Look! This is my mother.
(____) Oh! She's beautiful.
松鼠将松子埋藏在地下,在适宜的条件下,埋藏的松子就会萌发,这体现了动物在生物圈中的作用是( )