相关问题推荐
翻译句子。
晚饭你喜欢吃什么？________________________
他喜欢早饭吃鸡蛋。________________________
赛跑明星们每天吃大量的健康食物。________________________
我弟弟午饭喜欢吃花椰菜、鸡肉和苹果。________________________
成龙是电影明星。________________________
When British TV chef Jamie Oliver launched his‘Feed Me Better'campaign in 2004 in schools in the Greenwich area of London with the aim of improving the diet of British schoolchildren,some people were skeptical about the impact it would have.Oliver's highly-publicized television campaign to improve school lunches led to dramatic changes in the meals offered to pupils in the Greenwich schools.In order to achieve his aim Oliver needed to show schools how to swap（交换）cheap processed meals , which were high in saturated fat（饱和脂肪）,salt , and sugar , for healthier options.
Now,research at the Institute for Social and Economic Research(ISER)has shown that Oliver's experiment did not only help pupils eat more healthily,it also resulted in them performing better at school in English and Science and in helping schools reduce their rates of absenteeism（缺勤）.The ISER study, carried out by Michele Belol and Jonathan James,showed"substantial"positive effects,with the performance of 1 1 -year-old pupils eating Oliver's meals improving by up to 8% in Science and by as much as 6% in English.In addition,the number of children having authorized absences for sickness since 2004 showed a 14% decrease.
The ISER study analysed the academic test results of more than 13,000 children in Greenwich between 2002 and 2007 to evaluate the impact of Oliver's healthier meals on school performance.Pupils who sat exams in 2006-2007 had been on the new diet for at least 12 months,and the researchers found that the number of pupils reaching higher levels of achievement had clearly risen.The study also compared the results of the schools in Greenwich with those of pupils of the same age in seven other London areas who did not eat the meals created by Oliver.The researchers were surprised by the speed of improvements in the Greenwich pupils.They could find no other explanation for the results except for the healthier and more nutritious meals created by Oliver.
Commenting on ISER's findings,Oliver said he felt the research proved that he was right in his decision to remove fatty processed food and replace it with nutrient-rich（营养的）foods such as coconut （椰子）,fish, and broccoli（花椰菜）.He commented that “we could see that it made them calmer and therefore able to learn”. The healthier diet has helped schoolchildren improve academically.A:Right B:Wrong C:Not mentioned
以下是有关DNA粗提取实验的阅读材料：
A．核酸极不稳定，在较为剧烈的化学、物理因素和酶的作用下很容易降解。在制备DNA时要加入DNA酶（水解DNA的酶)的抑制剂——柠檬酸钠，以除去Mg，防止DNA酶的激活。
B．核酸中的DNA和RNA在生物体内均以核蛋白（由核酸和蛋白质组成)的形式存在，DNA核蛋白在2mol/L的NaCl溶液中溶解度很高，但在0.14mol/L的NaCl溶液中的溶解度很低；而RNA核蛋白易溶于0.14mol/L的NaCl溶液。
C．用苯酚处理，可使蛋白质变性，且留在苯酚层内；在DNA溶液中加入2.5倍体积分数为95%的酒精，可将DNA分离出来。此时DNA十分黏稠，可用玻璃棒搅成团取出。
D．DNA在强酸环境下，水解产生脱氧核糖等小分子物质，它与二苯胺酸性溶液反应，能生成蓝色化合物。
E．实验材料与仪器：柠檬酸钠溶液、石英砂、0.14mol/L的NaCl溶液、2mol/L的NaCl溶液、蒸馏水、苯酚、体积分数为95%的酒精、二苯胺试剂、浓硫酸、花椰菜、研钵、烧杯、漏斗、玻璃棒、量筒、石棉网、酒精灯、吸管、试管等。
F．实验步骤：研磨得匀浆→过滤得滤液→滤液稀释6倍→离心处理得沉淀物→沉淀物再溶解→加苯酚静置后去上层清液→提取出DNA→DNA鉴定。
请阅读以上材料完成下列问题：
（1)研磨时，取10g花椰菜，加适量的石英砂和____\_、________。
（2)将滤液稀释6倍，其目的是_______。
（3)取沉淀物，置于2mL2mol/L的NaCl溶液中，使DNA核蛋白再次溶解，再加2mL苯酚充分振荡后静置，待其分层后，弃去上层的苯酚。该步骤的目的是除去__________。
（4)如何将剩余溶液中的DNA提取出来？
（5)如何证明提取的物质确实是DNA？