certain

Completely sure about something, with no doubt; not used before a noun.

• I'm certain I locked the door.
  Kapıyı kilitlediğimden eminim.
• Are you certain about the time of the meeting?
  Toplantının saatinden emin misin?

Used before a plural noun to talk about particular people or things without saying exactly which.

• There are certain rules that everybody must follow.
  Herkesin uyması gereken belirli kurallar vardır.
• Certain foods can cause allergies in children.
  Bazı yiyecekler çocuklarda alerjiye neden olabilir.

Known to be true, or sure to happen.

• It is certain that prices will rise next year.
  Gelecek yıl fiyatların artacağı kesin.
• The team looks certain to win the cup.
  Takımın kupayı kazanacağı kesin görünüyor.

Some, but not very much, used in "a certain amount" or "to a certain extent".

• There is a certain amount of risk in every business.
  Her işte belli bir miktar risk vardır.
• I agree with you to a certain extent.
  Sana bir ölçüde katılıyorum.

Used before a quality that is real but difficult to describe exactly.

• The old town has a certain charm.
  Eski şehrin kendine özgü bir çekiciliği var.
• There was a certain sadness in her voice.
  Sesinde tarifi zor bir hüzün vardı.

Used before a person's name to show that the speaker does not know that person.

• A certain Mr Smith called while you were out.
  Sen yokken Smith adında biri aradı.
• The house was bought by a certain Dr Jones.
  Ev, Dr. Jones diye biri tarafından satın alındı.