필요need; necessity; requirement 중요importance 필요량requirement; amount needed 필요성necessity; need 강요coercion; pressure 불필요being unnecessary 소요requirement 수요demand 요구request; demand 요소element; component; factor; requisite

신청application 청첩장invitation card; invitation letter 청혼marriage proposal 초청invitation 초청장invitation; invitation letter 신청곡song request 신청서application form 신청인applicant; petitioner; claimant 신청자applicant; petitioner; claimant 요청request; appeal

교과서textbook 도서관library 독서reading 서류document; papers 서점bookstore 엽서postcard 추천서letter of recommendation; letter of reference 가입서registration documents 계산서check; bill 계약서contract; written agreement