在河北省境内采集207个表层土壤样品，测定其中的七氯含量。
207 top soil samples were collected from Hebei province and the contents of heptachlor were measured.
好，氯有七个，跟氟或者在那一列，的其它元素一样。
All right. So it's 7 that are in chlorine, it's the same as fluorine or any of the others in that row or in that group rather.
氯磺酰异氰酸酯可用于合成含氧、氮、硫等原子的四至七元杂环化合物。
Chlorosulfonyl isocyanate as an important intermediate was applied toward the syntheses of four to seven member heterocyclic compounds containing oxygen, nitrogen, sulfur atoms.
将母体染料的中位氯原子用氨基试剂亲核取代，衍生合成了五个中位仲胺七甲川菁染料。
Five derivative dyes from the parent dyes were obtained by similar nucleophilic substitution reaction in which five primary amines were employed as the nucleophilic reagent.
将母体染料的中位氯原子用氨基试剂亲核取代，衍生合成了五个中位仲胺七甲川菁染料。
Five derivative dyes from the parent dyes were obtained by similar nucleophilic substitution reaction in which five primary amines were employed as the nucleophilic reagent.
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