DNA复制主要发生在____（填“间期”或“分裂期”）．其原料是四种____ （填“核糖核苷酸”或“脱氧核苷酸”）．由于DNA在复制过程中，边解旋边____ ．分别以原来的两条脱氧核苷酸链作为模板，按照____ 原则合成新链，所以每个新DNA分子都保留了原来DNA分子中的一条链（一半），因此，这种方式称为____ 复制．

   The best way of learning a language is using it. The best way of learning English is talking in English as much as possible. Sometimes you'll get your words mixed up(混合) and people will not understand you. Sometimes people will say things too quickly and you can' t understand them. But if you keep your sense of humor(幽默感)，you can always have a good laugh at the mistakes you make. Don't be unhappy if people seem to be laughing at your mistakes. It's better for people to laugh at your mistakes than to be angry with you，because they don't understand what you are saying. The most important thing for learning English is："Don't be afraid of making mistakes because everyone makes mistakes."