Who are the top students in the world, do you know? Last week the Organization for Economic Co-operation Development (经济合作与发展组织) picked the best students in the world. They are Finnish (芬兰的). The OECD gave a test to 280 000 15-year-old students from more than 40 coun­tries and regions (地区) last year. The OECD wan­ted to know how well students were doing at school.
   Finnish students were No. 1 in the reading test and second in maths after Hong Kong students. Those from Japan and Finland were top in science. In the problem solving, Finnish students came sec­ond to those from South Korea. The test also showed Finland had more top students than the other countries.
   Finns (芬兰人) of your age have done a really good job but don't have a sense of envy. You can learn from them. Most Finnish students make good use of the Internet. Of course not for computer games, but for doing more exercises and finding out more information.
Libraries are also important. Finland spends a lot of money on them. Many students have a free card. They read for at least one or two hours a day.
   What do you usually do on the Internet? How often do you go to libraries?

下列城市中不属于我国14个沿海开放城市的是(    )

下列有关基因在染色体上的叙述，不正确的是（　　）

除去下列不纯物质中的少量杂质（括号内为杂质），请填入适当的试剂

（1）Cu（Al）____     （2）Fe₂O₃（Al₂O₃）   ____

（3）NO（NO₂） ____ （4）NaCl溶液（Na₂CO₃） ____．