题目

某同学按如下步骤对三种未知金属展开探究： (1)将它们编号为X、Y、Z； (2)取样，分别加入到CuSO4溶液中，发现X、Z表面出现红色物质而Y却没有； (3)取X、Z大小相等的颗粒，分别加入到溶质质量分数相等的稀硫酸中，发现X表面产生气泡的速度明显比Z快。则X、Y、Z的金属活动性由强到弱依次为  (  ) A．X>Y>Z        B．X>Z>Y      C． Z>Y>X       D．Z>X>YDoctors tell us that holidays are necessary. We must rest from 　1　 for a week or two weeks every year. “If it is possible，”they say, “we must 　2　 our homes and go to another 　3　 of the country. We must go 　4　 for a holiday. Then after the holiday, we are 　5　 home fresh and strong and ready for another 　6　 of work.” 　　This seems to be right for most adults(成年人) but not for 　7　. Some people don't like to leave their homes to stay in strange(陌生的) 　___8　. For young children it is usually quite different. They don't like to go far away from their 　9　. They like their homes 　10　 of all. (   ) 1. A. working   B. playing  C. swimming  D. running (   ) 2. A. stay       B. leave　 C. live        D. go (   ) 3. A. city　     B. town    C. village     D. part (   ) 4. A. after      B. up      C. down　    D. away (   ) 5. A. away      B. back    C. out        D. at (   ) 6. A. year       B. month   C. week      D. day (   ) 7. A. children    B. women  C. all        D. both (   ) 8. A. countries   B. parts    C. places      D. towns (   ) 9. A. cities      B. schools  C. families    D. homes (   ) 10. A. best      B. better    C. well       D. good