_______ is known to all,China will be an ______ and powerful country in 20 or 30 years’ time. A. That; advancing B. This; advanced C. It; advancing D. As; advanced 答案:D
如图,一张长方形纸沿AB对折,以AB中点O为顶点将平角五等分,并沿五等分的折线折叠,再沿CD剪开,使展开后为正五角星(正五边形对角线所构成的图形).则∠OCD等于( ) A.108° B.144° C.126° D.129°