principallyadv.主要地principaladj.主要的；首要的n.本金；资本；校长；主角；委托人；主犯principal series line主系线principal of prudence谨慎性原则principal focal point主焦点principal fuel supply主要燃料供给principal translation主平移principal determinant主行列式principal point angle主点角principal square root主平方根Principal of evidence举证责任principal outstanding未偿本金

1. The results showed that the predominant host animal of Dayangshu District was Apodemus agrarius, and presently it has changed to the mixed type of HFRS.
   结果表明，大杨树地区的疫源地性质是黑线姬鼠为主要宿主动物的肾综合征出血热自然疫源地，目前已演变为姬鼠型为主的混合型疫区。