A:
(1)用化学式填空:
①是___________________, ②是____________________________,
③是____________________, ④是 ___________________________;
(2)B的结构简式是 ____________________________________________;
A:
(1)用化学式填空:
①是___________________, ②是____________________________,
③是____________________, ④是 ___________________________;
(2)B的结构简式是 ____________________________________________;