The former is further divided into inevitable one and possible one, while the latter is divided into interrogative, imperial, expecting, unexpected, lucky and turning model adverbs.

There are three parts in this paper: First, interpreting the logic of Mohist School, and summarizing the western modern modal logic in order to get the modal term.

By using of modal expansion technique and Green s function method, the soun d rad iation characteristics of submerged finite cylindrical shells,which were partial ly covered with damping layers, were investigated in this paper.