eoje bame hyudaeponeul chungjeonhaji moshaeseo jigeum chinguege mesijireul mos bonaeyo.

I couldn’t charge my phone last night, so I can’t send my friend a message now.

Breakdown of eoje bame hyudaeponeul chungjeonhaji moshaeseo jigeum chinguege mesijireul mos bonaeyo.

• ~을: object particle
• 친구: friend
• ~를: object particle
• 어제: yesterday
• 지금: now
• 휴대폰: cell phone
• ~에게: dative particle
• ~에: time particle
• 밤: night
• 보내다: to send
• 못: cannot
• 메시지: message
• 충전하지 못하다: to not be able to charge
• ~해서: because / so

Questions & Answers about eoje bame hyudaeponeul chungjeonhaji moshaeseo jigeum chinguege mesijireul mos bonaeyo.

Why is 어제 밤에 written with -에? Could it be 어젯밤에 instead?

-에 marks a time point (“at / on”), so 어제 밤에 = “last night (at night).”
Yes, 어젯밤에 is also very common and a bit more “set-phrase-like.” Both mean “last night,” with no real difference in meaning in this sentence.

What do the particles 휴대폰을 and 메시지를 do here?

-을/를 marks the direct object.

• 휴대폰을 충전하다 = “to charge the phone” (phone = thing being charged)
• 메시지를 보내다 = “to send a message” (message = thing being sent)

What’s the difference between 충전하지 못해서 and 충전하지 않아서?

• 충전하지 못해서 = “because I couldn’t charge it” (inability / circumstances prevented it)
• 충전하지 않아서 = “because I didn’t charge it” (choice / intention, or just plain negation)

So 못해서 implies “I wasn’t able to,” not simply “I didn’t.”

Why does Korean use -아서/어서 in 못해서? What exactly does -해서 mean?

-아서/어서 connects clauses and often means because / so (cause → result).
Here, 못해서 is 못하다 + -아서:

• (어제 밤에) 충전하지 못해서 = “because I couldn’t charge it (last night),” leading to the result:
• 지금 … 못 보내요 = “I can’t send … now.”

There are two “can’t” ideas: 충전하지 못해서 and 못 보내요. Is that repetition normal?

Yes, it’s normal and natural here because they describe two different “inabilities”: 1) 충전하지 못해서: couldn’t charge the phone last night (cause)
2) (지금) 못 보내요: can’t send a message now (result)

English might also say: “I couldn’t charge my phone last night, so I can’t message my friend now.”

What’s the difference between 못 보내요 and 보낼 수 없어요?

Both mean “can’t send,” but nuance differs:

• 못 보내요: common, conversational, often implies practical difficulty or inability
• 보낼 수 없어요: more explicit “it’s not possible to send,” sometimes a bit more formal or emphatic

In this sentence, 못 보내요 sounds very natural.

Why is it 친구에게 and not 친구를?

Because send uses a recipient:

• 친구에게 = “to my friend” (recipient; -에게 is “to” for a person)
• 메시지를 = the thing being sent (direct object)

So the structure is basically: [recipient]-에게 + [thing]-를 + 보내다.

Can I say 친구한테 instead of 친구에게?

Yes.

• 친구에게: neutral / slightly more formal
• 친구한테: more casual, very common in speech

Both mean “to (my) friend” and fit this sentence.

Why does the sentence end with 보내요 (요-form)? What level of politeness is this?

-요 is the standard polite style used in everyday conversation with people you’re not extremely close to, or when you want to be polite.
A more casual version would be 못 보내. A more formal version could be 못 보냅니다 (less common in casual talk).

Is the subject missing? Do I need 저는/제가 somewhere?

Korean often omits the subject when it’s obvious from context. This sentence naturally implies I.
If you want to include it:

• 저는 어제 밤에 휴대폰을 충전하지 못해서 지금 친구에게 메시지를 못 보내요.
  Including 저는 adds a bit of emphasis/contrast (“As for me…”), but it isn’t required.