题目

如图所示的装置中可观察到电流计的指针发生偏转,M棒变粗,N棒变细,由此判断下表中所列M、N、P物质,其中可以成立的是 ( ) MNP A锌铜稀硫酸 B铜铁稀盐酸 C银锌AgNO3溶液 D锌铁Fe(NO3)3溶液 答案：选C。该原电池中M棒变粗,N棒变细,说明原电池反应时N棒溶解作负极,溶液中有金属析出在M棒上,M棒作正极。A、B选项中,电解质溶液分别为稀硫酸和稀盐酸,原电池工作时,不会有金属析出;C选项正极反应为Ag++e-====Ag,符合题意;D选项正极反应为Fe3++e-====Fe2+,不会有金属析出。动词填空。1. Mr Johnson likes ______ (watch) TV in the evening. 2. He ______ (go) fishing yesterday. 3. What ______ you ______ (do) this weekend?4. Listen! Someone ______ (sing) in the next room. 5. Mrs Beet ______ (drive) very fast to work every day.