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。
and an American-made dialysis machine needs the EU's okay before is hits the market in Europe.
而美国制造的透析仪也要得到欧盟的首肯才能进入欧洲市场。