Particles may not be the most exciting aspect of Japanese grammar, but they are absolutely essential. After you’ve mastered は and が, it is probably time for you to learn how to use も.
も might just be the easiest of all of the particles to get down. も is used in combination with a subject to indicate also or as well.
Chris is an American.
Adam is also an American.
You simply tack on も as you would with the also, but remember you must be consistent with your answer. For example in English you cannot say:
Chris is American.
Sam is also not American.
Japanese is the same. If you want to change from a negative to a positive or vice versa you use the particle でも.