Through or Thorough ?
Exemple : ‘’If you go through the door on your left you will find the dining room.’’
The words "through" and "thorough" are often mixed up due to their similar spellings. However the words have very different uses. "Through" is a preposition used to denote going from one end of something to the other.
Exemple : ‘’Your bedroom needs a thorough clean!’’
"Thorough" is an adjective which is used as a synonym of the words "complete" or "careful."