— What did you do last Saturday, Alex ?   

— Well , I ______to see a film , but in the end I stayed at home doing my homework.  [      ]

A. was going    

B. has gone    

C. went    

D. had gone  

将3.2g硫粉和16.8g铁粉混合均匀后放入试管里加热，充分反应，冷却，再加入足量稀硫酸，产生的气体体积（S.T.P）是

A． 6.72 L

B．3.36 L

C． 2.24 L

D．以上都不对