hwayoireneun chinguwa hamkke chilpan apeseo balpyo yeonseubeul haesseoyo.

On Tuesday, I practiced a presentation with a friend in front of the blackboard.

Breakdown of hwayoireneun chinguwa hamkke chilpan apeseo balpyo yeonseubeul haesseoyo.

• ~을: object particle
• ~에서: location particle
• 친구: friend
• ~는: topic particle

Questions & Answers about hwayoireneun chinguwa hamkke chilpan apeseo balpyo yeonseubeul haesseoyo.

Why is the time expression 화요일에는 using -에는 instead of just 화요일에?

-에는 combines the time particle -에 (“on/at”) with the topic particle -는, so it literally means “as for Tuesday.” It sets 화요일 as the topic of the sentence, often adding a nuance of contrast or emphasis (e.g. “On Tuesdays, (we at least) did X”). You could still say 화요일에 친구와 함께…, but 화요일에는 highlights the time more strongly.

What’s the difference between 에 and 에서 in this sentence? They both seem to mark location or time.

• -에 marks a point in time or destination (here, 화요일에 means “on Tuesday”).
• -에서 marks the place where an action occurs (here, 칠판 앞에서 means “in front of the chalkboard”).
  So you need 에 for the time expression and 에서 for the location of the activity.

Why is it 친구와 함께? Could I say 친구하고 함께 or 친구랑 함께?

All three mean “together with a friend,” but differ in formality and register:

• 친구와 함께: more formal/literary (와 attaches to consonants).
• 친구하고 함께: neutral/informal (-하고 is colloquial).
• 친구랑 함께: very casual (랑 is a contracted form of 하고).
  The meaning stays the same; choose based on your level of formality.

What does 칠판 앞에서 literally mean, and why use ?