By definition an exclusively difunctional monomer can only give rise to a linear polymer . 按照定义，一个特定的双官能单体，仅仅能得到线型聚合物。
2.
Clearly the principle requirement for a substance to be capable of forming a structural unit of a polymer chain is that it must be difunctional . 显然，对于能成为聚合物链结构单元的物质的基本要求是：它必须是双官能的。
