She plodded in her perpetuating circle of stove, worktable and sink as if nothing else existed.她只是在炉子 、 工作台和水井这个永恒的小天地里辛勤地劳动,好象其余的一切都不存在似的.Eons passed before life existed on the earth.经过数不清的年代以后, 地球上才有人类。The last paragra...
The optimum operation conditions of ion - exchange are obtained by intercross experimental method.运用正交试验得到了较佳的树脂交换—再生操作条件.These directions embody the trends of integration, intercross and qualification.可以看出沉积物搬运和底形研究的方向体...