かもしれない is an expression in Japanese that is often treated as a single word, but is actually the combination of the 助詞（じょし） (particle) かも, and the potential form of the う-Verb 知（し）る (to know) with the 助動詞（じょどうし） (auxiliary verb) ない attached. かもしれない is regularly translated simply as ‘might’, or ‘maybe’, but the literal translation is much closer to ‘even (A), we cannot know’.
To use かもしれない, attach it to the end of any verb, noun, な-Adjective or い-Adjective, in their non-polite (keigo) forms.

• 来年（らいねん）から観光客（かんこうきゃく）が増（ふ）えるかもしれない。
  From next year, the number of tourists might increase.
• あの建物（たてもの）は教会（きょうかい）かもしれない。
  That building might be a church.
• 今日（きょう）は無理（むり）かもしれない。
  It might not be possible today.
• そこの池（いけ）は深（ふか）いかもしれないから気（き） を付（つ）けてね。
  That lake over there might be deep, so please be careful.

As the う-Verb 知（し）る is part of this construction, it may also be altered to its polite-potential form, creating かもしれません.

• 明日（あした）は休（やす）むかもしれません。
  I might take the day off tomorrow.

Due to かもしれない being such a common grammar pattern in daily speech for expressing uncertainty about various things, several colloquial forms also exist. These are かも, and かもしらん.

• 明日（あした）は休（やす）みだからドライブするかも。
  I have a day off tomorrow, so I might go for a drive.
• 財布（さいふ）を家（いえ）に忘（わす）れてきたかもしらん。
  I might have left my wallet at home.

かも is by far the most common of these colloquial forms, with かもしらん potentially sounding a little bit rough/boyish.