中國簽證

中國大使館網站說：需要Original and photocopy of certification (marriage certificate, birth certificate, certification of kinship issued by Public Security Bureau or notarized certification of kinship) showing the relationship of family members between applicant and inviting individual. 這個證明一定需要嗎？打算讓姐姐給我寫邀請函，怎麽提供證明邀請人是我親姐姐呢？謝謝！