sebelum

In a sentence

• Saya makan pagi sebelum pergi ke sekolah.

  I have breakfast before going to school.

  'Sebelum' is used as a conjunction to indicate the action of having breakfast occurs prior to going to school.

• Sila datang sebelum pukul lapan.

  Please arrive before eight o'clock.

  'Sebelum' is used to describe arriving at a time prior to eight o'clock, showing its usage as a preposition.

• Dia mengulang kaji pelajaran sebelum peperiksaan.

  He reviewed his lessons before the exam.

  Here, 'sebelum' introduces the timing of the action in relation to the exam, acting as a temporal marker.