英语语法分析

That polyacetylenes are present in flames has been demonstrated many times.

已多次证实火焰中存在聚乙炔。

Aryl substituted polyacetylenes and their derivatives exhibit a lot of novel optical, electric, magnetic properties.

芳基取代聚炔及其衍生物呈现出光电磁等许多新颖的性能。