The PL of a freshly prepared colloidal solution (which shows slight increase during
the first 24 h) remains unchanged for 2 months in dark conditions
《高考英语备考1号·速效编》
《高考英语备考1号·写作编》
《高中英语晨读晚记》
《高中英语错题笔记》
《零起点考大学英语》