Retrieve part of database field

Hello Everybody,
I'm building a web site with PHP/Mysql and i want to add "search" functionality for the users. After searching for a while i found Full-Text search and i managed to fetch the correct rows from the table (according to users keywords). My problem is that i would like to show, in the search results, the sentence that contains the keywords. Is it possible to fetch from the field "contents" only the sentence that contains the keywords??
Also is it possible to expand the search in multiple tables without doing ot recersively.

Thanx in advance.