To the parents' worry, some middle school students are ______ computer games and completely forget

their studies.[ ]

A. crazy about    

B. very fond of    

C. concerned for  

D. serious about

根霉有性生殖时产生的有性孢子是（）倍体的（）孢子。火丝菌的有性孢于是于，（）中产生的（）倍体的。（）孢子。蘑菇的有性孢子是在（）上产生的倍体的（）孢子。