Most of the infective we think of us human infective started in other animals.我们认为,人类所感染的绝大部分的传染性疾病早在其他动物中已经流行.
在这个句子中,Most of the infective we think of us human infective 是主语;
其中,we think of us human infective 修饰 the infective 作后置定语
started 是谓语;
in other animals 是状语