About intersect...and other questions

[Dnt]

1. What is the difference between them(and why sometimes its 2 or 3 )
   2.Ive been using them by tutorials and Im successful in copy pasting but I dont "Understand" them(I mean spirit of them)... if you could explain them easily and practically I would really appreciate it( about their main usage...about their tricky way of use and how to use( if its possible for you pls all 3 mode)...and any other thing that has occurs to you and was useful)
   3.another thing...whats the meaning of trim in SU?
   4.one another thing... What is difference between making component and making group in important ways

[Wo3Dan]

What is selected where?

Being in top level
Selecting:
a) just one entity ==> With Model
(one face, one group or component/one edge doesn't do)
b) several entities ==> With Model or Selection

Being somewhere in editing context
Selecting:
a) just one entity ==> With Model or Context
(one face, one group or component/one edge doesn't do)
b) several entities ==> With Model, Context or Selection

[numbthumb]

Hi,
Please take a look at this, if you haven´t already:
http://www.aecbytes.com/tipsandtricks/2008/issue34-sketchup.html
http://www.tiebiaoji.info/modeling-guide/intersect-with-model.html
http://www.google.com/support/forum/p/sketchup/thread?tid=4adb3aa9bb7dc4c6&hl=en

[Dnt]

Thnx guys... I appreciate your helps