a thesis sentence for the following? ?

There are many ways I believe that reducing our dependence on oil might affect countries, in both positive and
negative aspects.

Easy.

If you've done the necessary research you can write a long, strong thesis statement. State your opinion or exactly what you're going to write about on the next paragraph, say you think that reducing the dependence of oil may make our country stronger because we wouldn't have to pay high rocketing prices for oil and use the money for something else. You can go on to the next paragraph explaining, and supporting your thesis which is what the essay is usually about anyway.

The Pros and Cons of Reducing Our Oil Dependancy.