achim tellebijeon nyuseureul bomyeonseo babeul meogeosseo.

I ate breakfast while watching the morning news on TV.

Breakdown of achim tellebijeon nyuseureul bomyeonseo babeul meogeosseo.

• ~을: object particle
• 먹다: to eat
• 보다: to watch
• 밥: meal

Questions & Answers about achim tellebijeon nyuseureul bomyeonseo babeul meogeosseo.

What does the connective ending -면서 indicate in 보면서?

-면서 attaches to a verb stem to show that two actions happen at the same time. Here, 보면서 means “while watching.” It tells us the speaker was eating breakfast at the same time as they watched the morning TV news.

Why is the verb 먹었어 in an informal style, and how would I make it polite?

먹었어 is the banmal (informal) past tense of 먹다. To make it polite (jondaetmal), change it to 먹었어요. The first verb’s connective form stays the same, so you’d say:
• Informal: 아침 텔레비전 뉴스를 보면서 밥을 먹었어.
• Polite: 아침 텔레비전 뉴스를 보면서 밥을 먹었어요.

Why isn’t there a particle after 아침? Shouldn’t it be 아침에?

Here, 아침 is part of the compound noun 아침 텔레비전 뉴스 (“morning TV news”), so no particle is needed. If you want to say “in the morning” as an adverbial time phrase, you use 아침에 and treat 텔레비전 뉴스를 separately:
아침에 텔레비전 뉴스를 보면서 밥을 먹었어.

Where is the subject of this sentence? Why is it omitted?

In Korean, subjects (and objects) are often dropped when they’re clear from context. Here the implied subject is “I” (나/저). If you need to emphasize it, you can say:
나는 아침 텔레비전 뉴스를 보면서 밥을 먹었어.

Could I swap the order of the actions, like 밥을 먹으면서 아침 텔레비전 뉴스를 봤어? Would that change the nuance?