The use of balloon shows how many gas (CO2) has been generated during the process.
回复:为什么要用气球封口,用瓶盖行不行?
所有跟帖:
• 谢谢! -ArgoMama- ♀ (0 bytes) () 03/21/2013 postreply 12:47:41
• 这是保证密封,但是里面会膨胀,所以给出空间, -丁庄秀园- ♂ (125 bytes) () 03/21/2013 postreply 18:35:20