식사를

In a sentence

• 나는 친구와 함께 식사를 했습니다.

  I had a meal with my friend.

  Here, '식사를' is used as a direct object to mean 'meal' which is the action being performed (having the meal).

• 이미 식사를 하셨나요?

  Have you already eaten a meal?

  In this sentence, '식사를' refers to the act of eating a meal, used in the context of asking if the action has been already done.

• 식사를 하기 전에 손을 씻으세요.

  Wash your hands before having a meal.

  In this example, '식사를' also represents 'meal', but is used here in a temporal context to set up an action happening before having a meal.