题目

阅读下面的短文，按照句子结构的语法情况和上下文连贯的要求，在空白处填入一个适当的同或用括号中所给词的正确形式填空，每空不超过两词。 My name is Nancy. I'm twelve old. I'm England. I am a middle school student. I'm in Class Three. I like green and blue. This (be) my new friend. Her is Wendy. She is thirteen. (her) is from England too. We are friends, we are in different(不同的) classes. Wendy is in Four. She likes red and yellow. All the (student) and teachers in her class like her. Wendy likes (swim), and she often swim在真核细胞中有三种RNA聚合酶，它们在不同的启动子处结合，转录不同的RNA。有关RNA聚合酶Ⅰ，下列叙述正确的是         A．它存在于核质，合成mRNA        B．它存在于核仁，合成mRNA C．它存在于核仁，合成tRNA         D．它存在于核质，合成tRNA E．它存在于核仁，合成rRNA