R is a replaceable function , e . g . acetoxy, methoxy, their acyloxy and alkoxy homologs or halo.
是取化基,如乙氧基、 甲氧基及它们的环氧和烷氧同系物或卤基。
The homologs of benzene are those containing an alkyl group or alkyl groups in place of one or more hydrogen atoms.
苯的同源物是于苯环中一个或多个氢原子的位置上以烷基取代的化合物。

词典释义: