Writing expository essay means explanation of some cases, events, processes and their analysis. For example, writing an essay on the topic historical surprises (historical events) you may start with the following:
Is there logic in historical process? Frankly speaking, to find the logic in such a chaotic process is very difficult. Nevertheless, researches of recent decades, studying factors affecting the historical process, offer different versions, quite interesting, but they are not fully explain the observed catastrophic processes of human life. But the fact that such studies exist, and hence it is possible to debate on the subject, gives a cause to think that glimmers of solving this problem are obvious
Then you have to write about some of the most interesting events and explain whether you agree or not. In simple words, you need to express your opinion. Restate the main point of your English essay at the end of your college essay writing.