表示：____里面有____个____

我国少数民族自治区主席、自治州州长、自治县县长依法全部由实行区域自治民族的公民担任，目前全国共有290多万名少数民族干部。这充分证明（  ）

①我国少数民族享有管理本民族自治地方内部事务的权力

②民族区域自治制度有利于维护国家的统一和安全

③我国认真贯彻落实民族区域自治制度

④确立自治区是民族区域自治制度的核心内容

    Mr. Brown lives on Green Street now. He wants to send a postcard(寄明信片) to his pen friend in Toronto, but he doesn't know where the post office is. “ where is the post office？” he asks his new neighbor Joe. “I want to send a postcard to Toronto.” “The post office is quite far from here，” answers Joe. “If you only want to post some letters(信件) or postcards, you needn't go to the post office. You can put them into a mailbox（信箱）down the street.”