题目

根据句子意思，填入合适的介词。 You should listen __________ the teacher in class. Are you ready __________ the class? There are two beautiful pictures __________ the wall. Happy Birthday! This is the present _________ you. We are having a sports meeting __________ the playground now. 答案：【小题1】to 【小题1】for 【小题1】on 【小题1】for 【小题1】in 解析: 略2．下列关于硝化细菌的描述中，错误的是（　　）A．其细胞内没有叶绿素B．细胞内有线粒体C．自身能合成有机物D．属自养生物