小明同学用如图所示的装置测定斜面的机械效率，实验记录结果如下表：

实验次数	斜面倾斜程度	物体重G/N	斜面高度h/m	沿斜面拉力F/N	斜面长s/m	有用功W有/J	总功W总/J	斜面的机械效率η
1	较缓	5	0.1	1.5	1	0.5	1.5	33.3%
2	较陡	5	0.2	2	1	1	2	50%
3	较陡	10	0.2	4	1	2	4	50%
4	最陡	5	0.3	2.4	1	1.5	2.4	62.5%

钞票的某些位置用荧光物质印上了标记，在紫外线下识别这些标记，是一种有效的防伪措施。某同学在较暗的环境中做了下列三次实验。

根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

    Food safety is a problem in all places around the world and people in different areas of the world prepare foods in different ways. The WHO released (发布) five simple rules for preparing food in a safe way. They call these rules the “Five Keys to Safer Food”.

Key 1: Keep clean

    ____People should wash their hands often — before touching food and while they are preparing food. People should wash all surfaces and equipment used for preparing food.

Key 2: Separate raw (生的) and cooked

    Raw foods should not touch prepared foods.____.

Key 3:____

    People should cook eggs and meat especially carefully. These foods may carry more micro-organisms (微生物) than other foods. Food like soup must be boiled for at least a minute to make it be cooked completely. It is also important that people re-heat cooked food completely.

Key 4: Keep food at safe temperatures

    When people finish eating, they should keep the left food in a refrigerator below 5℃and shouldn't store it for too long. At room temperature, about 20℃, the amount of micro-organisms can increase very quickly. But temperatures above 60℃ or below 5℃ control the growth of micro-organisms.____.

Key 5: Use safe water and raw materials

    ____. Damaged or old food may develop harmful chemicals as it gets older.

A. Cook completely

B. This key tells about the importance of washing

C. Eat healthily

D. They can live where we make food

E. People should use safe water and choose fresh foods

F. They cannot grow as quickly in a very hot or very cold environment

G. People should use separate equipment and tools for touching and preparing raw foods

－2.040×10⁵表示的原数为（  ）

阅读下面文言文，完成下列各题。
    蔡襄，字君谟，兴化仙游人。举进士，为西京留守推官、馆阁校勘。范仲淹以言事去国，余靖论救之，尹洙请与同贬，欧阳修移书责司谏高若讷，由是三人者皆坐谴。襄作《四贤一不肖诗》，都人士争相传写，鬻书者市之，得厚利。契丹使适至，买以归，张于幽州馆。庆历三年，仁宗更用辅相，亲擢靖、修及王素为谏官 ， 襄又以诗贺，三人列荐之，帝亦命襄知谏院。襄喜言路开，而虑正人难久立也。乃上疏曰：“朝廷增用谏臣，修、靖、素一日并命，朝野相庆。然任谏非难，听谏为难；听谏非难，用谏为难。三人忠诚刚正，必能尽言。君有过失，不救之于未然，传之天下后世，其事愈不可掩，此之谓彰君过，愿陛下察之，毋使有好谏之名而无其实。”夏竦罢枢密使，韩琦、范仲淹在位，襄言：“陛下罢竦而用琦、仲淹，士大夫贺于朝，庶民歌于路，至饮酒叫号以为欢。且退一邪，进一贤，岂遂能关天下轻重哉？盖一邪退则其类退，一贤进则其类进。众邪并退，众贤并进，海内有不泰乎！虽然，臣切忧之。天下之势，譬犹病者，陛下既得良医矣，信任不疑，非徒愈病，而又寿民。医虽良术，不得尽用，则病且日深，虽有和【注】、扁，难责效矣。”以母老，求知福州，改福建路转运使，开古五塘溉民田，奏减五代时丁口税之半。进知制诰，迁龙图阁直学士、知开封府。以枢密直学士再知福州。徙知泉州，距州二十里万安渡，绝海而济 ， 往来畏其险。襄立石为梁，其长三百六十丈，种蛎于础以为固，至今赖焉。又植松七百里以庇道路，闽人刻碑纪德。治平三年，丁母忧。明年卒，年五十六。乾道中，赐襄谥曰忠惠。
（节选自《宋史•蔡襄传》）
【注】和：秦和，古代名医。