It seems a well-known fact that subvarieties of a variety of general type containing a general point are also of general type. This fact is an essential property used to prove some extension theorems of pluricanonical forms on algebraic varieties of general type, see for example the very nice survey on extension of pluricanonical forms

www-fourier.ujf-grenoble.fr/ECOLETE/2007/cours/pacienza.pdf.

I want to know why this is true? Is there any thing more we can say about the relation between the canonical line bundle of a variety and that of subvarities of codimension no less than 2.