问题 问答题 简答题

简述水稻品种南北相互引种后预期的效应。

答案

参考答案:

在引种方面的应用纬度和海拔相近的地区,东西方向相互引种,因日长和温度条件相近,易于成功。北方的品种南引,因生育期间的日长变短,温度提高,品种的生育期缩短,往往生长量减少,不利产量形成。南种北引,因生育期间的日长变长,温度降低,品种的生育期延长,只要种植制度允许,能安全齐穗,即能发挥其增产潜力。高海拔品种引至低海拔,生育期的变化与北种南引相似;低海拔品种引至高海拔,与南种北引相似。

单项选择题
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完形填空
     I always remembered the first time I took part in an English composition competition. "Right! Dean
would be the __11__ of our class to participate in the English composition competition," my classmates
said.
     I was too __12__ to speak when I heard what my classmates said. In order not to __13__ short of
my classmates'__14__, I trained myself very hard for the hope of being the __15__ of the competition,
which would take place a month later. I __16__ a lot of vocabulary, sentence structures and __17__
rules and read many good or renowned articles. Not having I __18__ pretty well, the day came. Every
candidate __19__ me looked so wellprepared and __20__. "Only 1. 5 hours. Start," a supervisor
suddenly said. Seeing the __21__ "What do most teenagers concern nowadays?" I was nervous and
got __22__ block. What's worse, other candidates had begun writing.  Moments later, I __23__
myself, took a deep breath, and began brainstorming ideas __24__ the topic. I quickly wrote down the
composition structure, central theme, and __25__ necessary elements. As the finishing time was
__26__, I tried my best to accelerate my writing. Unfortunately, __27__ my failure of time management,
I left my composition incomplete. My final draft looked like a robot __28__ legs were broken.
     The result came out two weeks later. To my surprise, I got the second prize! All my classmates
cheered for me. This encouraged me a lot. __29__ I was not the first prize winner, I could still __30__
pride and happiness spreading around me.                 
( )1. A. player      
( )2. A. proud      
( )3. A. get        
( )4. A. promises    
( )5. A. success    
( )6. A. memorized  
( )7. A. grammar    
( )8. A. remembered  
( )9. A. besides    
( )10. A. easy      
( )11. A. problem    
( )12. A. writer's  
( )13. A. persuaded  
( )14. A. with      
( )15. A. another    
( )16. A. approaching
( )17. A. thanks for
( )18. A. of which  
( )19. A. However    
( )20. A. smell      
B. choice      
B. delighted    
B. be          
B. expectations
B. beater      
B. copied      
B. phrase      
B. prepared    
B. except      
B. nervous      
B. idea        
B. teacher's    
B. said        
B. towards      
B. the other    
B. accessing    
B. due to      
B. which        
B. As a result  
B. touch        
C. representative  
C. nervous        
C. lose            
C. dreams          
C. winner          
C. read            
C. pattern        
C. started        
C. except for      
C. interested      
C. topic          
C. thinker's      
C. encouraged      
C. at              
C. other          
C. finishing      
C. as a result    
C. whose          
C. Worse still    
C. sense          
D. person      
D. surprised    
D. fall        
D. words        
D. victory      
D. wrote        
D. term        
D. completed    
D. as well as  
D. unconfident  
D. question    
D. composer's  
D. calmed      
D. for          
D. others      
D. ending      
D. on account  
D. that        
D. Although    
D. realise