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 .
