唔該幫下我....

我作文唔係幾好,不過希望幫到你:
你可以作:
你想點用部時光機(e.g.如果我有一部時光機,我會用它回到小時候......)
or
你想發明部時光機,並提出部時光機點幫到大眾(e.g.我你想發明一部時光機,因為......)

希望幫到你啦!

You may write what you will do and where you will go if you have this machine and you have to give reasons. You may then write a story of what has happened in the past and how you changed the ending of it and what the results are