first intermediate host造句怎么写

The results confirm the first intermediate hosts are several species of Tricula, and the second intermediate hosts are Potamon chinghungense and P. hispidum.

Two species of snails, namely, Tricula fujiansis and Semisulcospira libertina were found, but only the former was the first intermediate host. The infection rate of snails was 0.7%(4/569).

Investigation into the ecology of first intermediate hosts of Pagumogonimus skrijabini in in Xingshan County,the Three Gorges reservoir area