Sampling and preparation of samples for the determination of chemi .

钢和铁化学成分测定用取样和试样制备。

Already I have reviewed general chemistry , organic chemistry , and quantitative chemi .

我已经复习了普通化学，有机化学和食品化学。

Coexistence with mankind has given rise to the sort of tough plants that flourish despite the worst we can do - hoeing pulling burning and more recently spraying the fields with herbicidal chemi .

与人类的共处使得这种顽强的植物能够在我们无所不用其极的摧残下依然繁盛着又是锄、又是拔、又是烧，近年来更多的是喷洒除草剂。