2022英语周报华东北师大版答案

5,D解析】搭建1个脱氧核苷酸需要1个磷酸、1个脱氧核糖、1个碱基、1个脱氧核糖和磷酸之间的连接物,而连接物只有14个,因此能搭建出14个脱氧核苷酸,A选项镨误:搭建1个脱氧核苷酸需要1个脱氧核糖和磷酸之间的连接物,1条脱氧核苷酸链中相邻两个脱氧核苷酸之间需要1个脱氧核糖和磷酸之间的连接物,因此所搭建的DNA分子片段最长含有4个碱基对,含有4个碱基对的DNA分子片段最多有44种,但四种碱基的数量有限,因此能搭建出的DNA分子模型种类小于4种,B、C选项错误,D选项正确

书面表达(满分25分)One possible versionDear JohnThank you very much for your concern about my study during the epidemic. Im now conducting online learning atChina has postponed the start of the new school semester over safety concems as ysghts COVID-19ntbreak. Millions of Chinese students restricted to their homes have started online lrequired to open online curricula. Its purpose is to ensure that students are.guided study at home so thatstudents’ study won’ t be affectedDoes your country organize similar learningh项mm,mmmforward to your reply!Y

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