Now you will find the prepositions from the given English phrases or sentences. The examples of prepositions are followings

of, from, on, by, in, into, with, at, within, ...

Mark the circle on the word that you think a preposition. Now you don't have worry about which word is a preposition or not, just mark the words mentioned above. Let me show you an example;

This is a very simple process in which you will be familiar with English treatment very efficiently. The process that has been developed for more than ten years and introduced in this site is called the graphic transformation.

With the passage given above, find the word thay you think preposition and put a circle on the word. You will get the followiing results. Sometimes you can find all the prepositions in the given passage, you do a perfect job. However, most of the students can not make it. No problem. Just follow the process that will be given to you in our goTOEFL.com site. Someday, you will get a very high proficiency after making a step by step work.

You have to do it by yourself.
Compare your job with the result shown above. You may find one or two "of" and miss one or two in other place. It is the problem of accuracy. Just follow the directions given to you, and do as you are told. One thing you have to remind is to do your best. What is important is for you to separate what you know from what you don't know. And more important thing is how much you represent what you know.