The agreement ended six-month negotiation. It was signed yesterday6/30The agreement ended six-month negotiation. It was signed yesterday.The agreement which was signed yesterday ended six-month negotiation.The agreement which ended six-month negotiation was signed yesterday.The agreement which was signed yesterday lasted six months.The negotiation which lasted six months was signed yesterday.Giải thíchChọn đáp án A Giải thích : mệnh đề quan hệ xác định, which thay cho danh từ chỉ vật.