를 막으려고

… to prevent

→ 를

phrase Uncommon #7,585

… to prevent The object particle 를 marks what is being prevented; 막으려고 expresses the purpose of preventing it. The particle changes to 을 after a consonant-ending noun.

KO: 사고를 막으려고 안전벨트를 매세요.

EN: Wear a seat belt to prevent an accident.