These are three simple paragraphs.  Each has a clear topic sentence at the beginning and is supported by sufficient details.
Paragraphs adapted from English Made Easy: A Canadian Rhetoric and Handbook by Judi Jewinski
                                  Classes Within Classes

    There are essentially three kinds of students, all of which may be found in any classroom.  The first kind is the bookworm, characterized by a serious expression, ink-stained fingers, an armload of books and a persistent refusal to participate in any activity not involving research.  At the opposite end of the scale is found the second type: the social butterfly.  This student rarely carries anything but an activities calendar for recording the dates of parties to attend and the names of people to go out with.  For the social butterfly, the classroom is merely a place to make new friends.  Most students, however, belong to the third category, somewhere in between the extremes of the first two.  These people are appropriately studious in class and for a few hours every night, but they also know how to relax by going to an occasional movie or party.  While teacher may be awed by the bookworm and frustrated by the butterfly, it is this third type of student who provides them with greatest professional satisfaction.

                                 
The Research Paper: A Long Journey

    There are five steps to writing a research paper. Each requires considerable time and effort to complete before going on to the next.  First, the writer must decide upon a topic.  This step may involve discussing the assignment with the teacher or with classmates so that the writer understands what research must be undertaken.  The next step is to do this research, by going to the library, searching on the internet, or by reviewing class notes and course textbooks.  For the third stage, the resulting information must then be classified as general material and specific support, allowing the writer to prepare a detailed outline for the paper. Once the outline has been set up, the writer can move to the next, and possibly longest, stage: the actual writing of an introduction body and conclusion.  The final step involves proofreading.  It is not enough merely to rewrite the paper neatly or to have it typed; the writer must also check it carefully to eliminate errors in logic, style and grammar.  Only once these five stages have been satisfactorily completed, a project requiring at least three days, can the writer presume to turn the polished essay in to the teacher for grading.

                                                     
Home Shopping

    Shopping on the internet is much more convenient than shopping in person.  Relaxing at their desks, customers can forget the frustrations and pressures of traditional shopping.  For one thing, the internet eliminates the need for transportation to a department store and the problem of finding a parking space.  More importantly, there is no salesclerk to pressure the internet shoppers into buying something they do not want or to frown disapprovingly if they simply want to browse.  Best of all, if the customers do not find exactly what they have been looking for on the internet, they will not feel that they have wasted their time on a pointless excursion; they will have invested perhaps fifteen minutes instead of a few hours, and their feet and legs will not be aching either.  It is no wonder, therefore, that many people do their shopping at home and that department stores are beginning to put their products online.