“约”的英语可以翻译为：make an appointment，arrange，ask or invite in advance，restrictpact，agreement，appointment，a surnameeconomical，frugal，simple，brief（大概） about，around，approximately ...
植物由于具有螯合机制可能影响土壤的化学特性.Plants may possibly influence soil chemistry by the possession of chelating mechanisms.确定螯合 -- 溶剂萃取法所得到的检测限颇为困难.It is difficult to define the detection limits obtained by chelation - solvent extract...