part可數嗎？如果可數，Here is part of his talk.此句如何解釋。

part n.[c][u] a piece of sth.

* be part of=be a part of

e.g.Falling over is part of learning how to ski.=Falling over is a part of learning how to ski.

* part of = a part of (壹小部分) / parts of （大部分）