1. His mouth was half open with dribbling saliva.
    他的嘴半张着, 淌着口水。

2. Over the periods their saliva, a mild, digestive juice like our own,
    蛇的唾液本来和我们人的消化液一样柔和，但经过漫长的时间，

3. In the conversion of saliva into poison, one might suppose that a fixed process took place.
    人们可能认为，唾液转变成毒液，其中有固定的程序。