英语语法分析

Four molecules of porphobilinogen combine to form a linear tetrapyrrole.

四个胆色素原分子结合形成一个线性四吡咯。

This paper was aimed to study the photodynamic effects of tetrapyrrole compounds on insects and rheumatoid arthritis models.

本文主要对四吡咯化合物的光动力灭蝇活性及抗类风湿性关节炎的作用进行研究。