题目

下列关于DNA复制过程的正确顺序是: ①互补碱基对之间氢键断裂    ②互补碱基对之间形成氢键    ③DNA分子在解旋酶的作用下解旋  ④以解旋后的母链为模板进行碱基互补配对  ⑤子链与母链盘旋成双螺旋结构 A．①③④②⑤        B． ④①②⑤③         C．①③⑤④②        D．③①④②⑤ 短文改错 Since my primary school days I have always found it 1．________ easily to get on well with boys．Unfortunately, this 2．________ means there have always had many rumors about me． 3．________ When I was primary school pupil, I had a friend 4．________ who was a boy．We often played with games and wrote 5．________ homework together．We were good friends shared happiness 6．________ and sorrow．But our friendship stopped because a 7．________ rumour which we loved each other．I couldn’t 8．________ bear it and paid no attention on him from then on． 9．________ As a result, we never saw each other again before we graduated from primary school． 10．________