You are welcome to answer questions posted in the Ask a Teacher forum as long as your suggestions, help, and advice reflect a good understanding of the English language. If you are not a teacher, you will need to state that clearly at the top of your post. Please note, all posts are moderated by our in-house language experts, so make sure your suggestions, help, and advice house the kind of information an international language teacher would offer. If not, and your posts do not contribute to the topic in a positive way, they will be subject to deletion.
Our Linguistic Book said the typical form of excentric is preposition phrases ,while the typical form of endocentric is noun phrase .But I'm stlll not quite understand what is excentric and endocentric.
A lot of linguistics is fairly simple, but hides behind rather grand terms. Another difficulty is that many of the terms are confusing to the extent that they seem designed to make things more difficult for students than they need be.
exocentric & endocentric (in our Linguistic Book) 
Linear Mode
