naneun sukjereul hagi jeone soneul ssiseo.

나는 is made up of 나 (informal “I”) plus the topic particle 는. It marks “I” as the topic.

• In casual speech you often drop it if the subject is clear.
• In polite or formal speech you’d use 저는 instead of 나는.

It breaks down as follows:

1. 숙제 “homework”
2. 를 object particle (since 숙제 ends in a vowel, you attach 를)
3. 하다 “to do” → stem 하
   • nominalizer -기 → 하기 “doing”
4. 전에 “before”
   Put together: 숙제를 하기 전에 = “before doing homework.”

They’re both object markers:

• Use -을 if the noun ends in a consonant (e.g., 손 → 손을).
• Use -를 if the noun ends in a vowel (e.g., 숙제 → 숙제를).

씻어 is the informal low-register present tense (declarative). Korean has several speech levels:

• 씻어: informal (친구 사이, diary-style)
• 씻어요: informal polite (most everyday conversations)
• 씻습니다: formal polite (announcements, formal settings)

Yes, you can say 손을 씻고 숙제를 해 (“wash your hands and do homework”).

• -고 lists actions in sequence without highlighting “before.”
• -기 전에 emphasizes “do Action A strictly before Action B”—often used for precautions or rules.

You can use -고 나서 or -한 후에:

• 숙제를 하고 나서 손을 씻어
• 숙제를 한 후에 손을 씻어