Fifty-litre carboy would be the most economical size. Carboys may be retained without charge for two months.
50升的瓶子应是最经济的尺码,这些瓶子可免费保存两个月。
The killing of the bison changed the whole wildlife of the plains. With fewer bison, grass shoots were not eaten, so grass did not grow as strongly.
屠宰野牛改变了平原的全部野生生物。野牛少了,嫩草没有牛来吃了,草就长得不粗壮。