【简答题】—Did you visit the famous cultural relics last month? —No,we _________ it,but we spent too much time shopping. A.could have visited B.must have visited C.can’t have visited D.shouldn’t have visited...
【单选题】如图为 DNA 分子结构示意图,相关叙述正确的是 ( ) a . 2 和 3 相间排列,构成了 DNA 分子的基本骨架 b . 4 的名称是胞嘧啶脱氧核苷酸 c . 9 是氢键,其形成遵循碱基互补配对原则 d . DNA 分子中特定的脱氧核苷酸序列代表了遗传信息 e . 3 占的比例越大, DNA 分子越不稳定 f . 5678 依次代表 A 、 G 、 C 、 T
【简答题】We experienced and unusual weekend last month! Early in the morning, we went to the country and spent a whole day wild flowers. the car full of we were going home. On our way back, my wife a bookshelf...