金代创设了传送紧急文书的（） A.保密制度 B.军邮制度 C.帖黄制度 D.急递铺制

因为水稻是自花授粉作物，“自花授粉作物自交不衰退，因而杂交无优势”的论断明白无误地写在美国著名遗传学家辛诺特和邓恩的经典著作、五六十年代美国大学教科书《遗传学原理》中，由此有人嘲笑“提出杂交水稻课题是对遗传学的无知”。

　　在理论与事实发生矛盾时，袁隆平的态度是尊重权威但不崇拜权威，不能跟在权威后面亦步亦趋，不敢越雷池一步。他不迷信权威的每一个观点。他知道，根据自己直接观察到的一些事实表明水稻具有杂交优势，“无优势”论是没有试验依据的推论，这一推论与自交系的杂交优势现象相矛盾：玉米自交系继续自交不再引起衰退现象，但杂交能产生强大的优势。而天然的自花授粉植物品系（天然自交系）自交也不退化，为什么杂交却不能产生杂种优势呢？袁隆平坚信搞杂交水稻研究有前途，勇敢地向“无优势”论这一传统观念挑战，从而拉开了我国水稻杂种优势利用的序幕。

　　袁隆平认为，水稻的杂交优势利用只有两条路可走：一条是进行人工去雄，如果用人工去雄杂交，就得一朵花一朵花进行，产生的种子数量极为有限，不可能在生产上推广应用。再一条路就是培育出一个雄花不育的“母稻”，即雄性不育系，然后用其他品种的花粉去给它授粉杂交，产生出用于生产的杂交种子。然而国内外都没有这一先例，国际上有著名学者断言：不可能。还有学者认为，像水稻这样一朵花只结一粒种子的“单颖果作物”，利用杂种优势必然制种困难，无法应用于生产。在独立开展杂交水稻研究很长时间之后，袁隆平才从国外资料中了解到，早在1926年，美国的琼斯就发现了水稻雄性不育现象。最早开展这项研究的是日本的科学家，当时是50年代。此外美国、菲律宾的科学家也相继开始了这项研究。尽管实验手段先进，但都因这项研究难度确实太大，无法在生产中得到应用。

　　袁隆平不打算退却，他很清楚他拥有的有利条件是其他国家科学家少有的：进行这项研究，中国有中国的有利条件，中国是古老的农业国，又是最早种植水稻的国家之一，有众多的野生稻和栽培稻品种，蕴藏着丰富的种质资源；有辽阔的国土和充足的光温条件，海南岛是理想的天然温室，育种者的乐园；更重要的是我们有优越的社会主义制度，可以组织科研协作攻关；有党的正确领导，任何困难都可以组织力量克服。直到今天，袁隆平都对为攻克杂交水稻难关在全国13个省区的18个科研单位进行的科研大协作感慨不已，认为没有这样的大协作，杂交水稻研究决不会取得今天这样世界瞩目的成果。

　　1964年7月5日，“泥腿子专家”袁隆平又走进了安江农校的稻田，去寻找水稻的天然雄性不育株。他头顶烈日脚踩淤泥弯腰驼背去寻找这种天然雄性不育株，已是第16天了。突然他的目光停留在一棵雄花花药不开裂，性状奇特的植株上，这正是退化了的雄蕊。他马上把这株洞庭早籼天然雄性不育株用布条标记。袁隆平欣喜异常，水稻雄性不育植株，终于找到了。

　　两年后，袁隆平的一篇论文《水稻雄性不孕性》发表，它证明了袁隆平培育杂交水稻的理论设想是科学的，是切实可行的。袁隆平的发现，开创了世界水稻研究的新纪元。

小题1:选文首段提出美国著名遗传学家的经典著作和有人对袁隆平的嘲笑有什么意义？（4分）

小题2:怎样理解袁隆平“开创了世界水稻研究的新纪元”。（5分）

小题3:通讯是侧重于写人物的新闻体裁，在选材上注重突出多角度表现和刻画人物形象，你认为本选段主要是从什么方面来表现“杂交水稻之父”袁隆平的？（6分）

商业银行不得向关系人发放( )。

A．信用贷款

B．担保贷款

C．抵押贷款

D．质押贷款

Fifteen percent of US teenagers aged 12 to 17 who own mobile phones have received nude（裸体）or nearly nude images of someone they know, according to a survey released on Tuesday.

Only four percent of mobile phone-owning   1 in that age group have sent sexually suggestive pictures of themselves, a practice known as "sexting,"   2 the Pew Research Center’s Internet & American Life Project.

The Pew survey found that girls and boys were equally as likely to have sent a suggestive picture to   3 person and 4  teenagers were more likely to have engaged in "sexting."

Eight percent of 17-year-olds with mobile phones have sent a sexually provocative（刺激的） image  5  texting and 30 percent have 6   a nude or nearly nude image on their phone.

Only four percent of 12-year-olds have sent suggestive images of   7 .

Amanda Lenhart, a senior research specialist at Pew and the author of the report, said sexually suggestive images have become a   8  of "relationship currency" for teens.

"These images are    9  as a part of or instead of sexual activity, or as a way of starting or  10  a relationship with a significant other," she said. "And they are also passed 11  to friends for their entertainment value, as a joke or for   12 ."

"The desire for risk-taking and sexual exploration during the teenage years  13  with a constant connection via mobile devices creates a 'perfect storm' for sexting," said Lenhart.

"Teenagers have always grappled with issues around sex and   14  , but their coming-of-age mistakes transgressions have never been so easily   15  and stored for others to see," she added.

The survey found that teens with unlimited text messaging plans were more likely to receive "sexts"   16  images of people they know. About 75 percent of mobile phone owning teens have unlimited plans.

Among this group, Pew said 18 percent reporting receiving "sexts"    17   with eight percent of teens on    18  data plans and three percent of teens who pay per message.

According to Pew, 58 percent of 12-year-olds own a mobile phone and 83 percent teens aged 17   19   .

Pew noted that a number of US states are grappling with how to 20  "sexting" among minors and some legislatures(立法机关) have stepped in to consider laws that would downgrade charges from felonies（重罪） to misdemeanors（轻罪）.

Pew conducted telephone interviews with 800 teens aged 12 to 17 and their parents between June 26 and September 24.

(   ) 1. A. teens                  B. adults               C. students            D. parents

(   ) 2. A. referring to               B. reporting          C. saying              D. according to

(   ) 3. A. other                 B. another             C. others               D. the other

(   ) 4. A. younger             B. fewer                      C. older                D. more

(   ) 5. A. by                     B. in                    C. on                    D. through

(   ) 6. A. accepted             B. received           C. sent                  D. mailed

(   ) 7. A. others                B. themselves        C. himself             D. herself

(   ) 8. A. habit                  B. system              C. method             D. form

(   ) 9. A. shared                B. limited             C. tasted                      D. controlled

(   ) 10. A. remaining         B. gaining             C. maintaining      D. obtain

(   ) 11. A. along                      B. by                    C. as                    D. for

(   ) 12. A. joy                  B. fun                  C. excitement        D. delight

(   ) 13. A. compared         B. followed           C. combined         D. went

(   ) 14. A. friendships       B. scholarships      C. relatives           D. relationships

(   ) 15. A. transmitted       B. transformed      C. formed             D. switched

(   ) 16. A. containing               B. concluding        C. including          D. concerning

(   ) 17. A. comparing               B. compared         C. connected         D. joined

(   ) 18. A. limited             B. unlimited          C. few                  D. little

(   ) 19. A. have                B. same                C. do                    D. too

(   ) 20. A. do with            B. deal with          C. remove             D. ban

人的生理需要和动物的生理需要并无本质不同。（）

处方一般不得超过几日用量（）

A.1日

B.3日

C.5日

D.7日

E.10日