题目

用下列装置进行实验，不能达到实验目的是（ ） A . 收集O2 B . 干燥CO2 C . 验证CO2性质 D . 监控气体流速 答案：A阅读理解 　　It' s five in the afternoon. It' s time to go home. But we must clean our classroom. There are five students in our team. Now there are only three. Wang Hai and Lin Ping are flying a kite. I am saying to them. "One of us is carrying water, and the other is cleaning the floor. Come up and clean our classroom." Look! Wang Hai is carrying some chairs onto the desks with me. What is Lin Ping doing? We can't see him in our classroom. Where is he? Do you know? 1. It' s time for the students to ______ . [　　] A. go to school B. fly a kite C. play D. clean their classroom 2. ______ of the students are cleaning their classroom. [　　] A. Two　　　B. Three　　　C. Four　　　D. Five 3. Wang Hai isn' t cleaning the classroom. Because ______ . [　　] A. he doesn' t like to clean the classroom B. it' s five in the afternoon C. it' s time to go home 　　　　　　　　　　　　　　　　　　 D. he is flying a kite 4. What are the students doing? ( Which is wrong? ) [　　] A. They' re carrying water.　　   B. They are carrying chairs onto desks C. They are cleaning the floor D. They are writing on the blackboard 5. Who isn' t in the classroom? [　　] A. Wang Hai　　　B. The kite　　　C. Lin Ping　　　D. All are in it