abolish;annul; nullify; put an end to ～婚約annul a marriage contract/～契約defeasance /～強(qiáng)迫勞動(dòng)abolish forced labor /～奴隸制、奴隸販賣及類似奴隸制的制度與習(xí)俗abolish slavery,slave trade and institutions and practices similar to slavery /～協(xié)議nullify an agreement