D．Being monitored by Suvorov and other scientists.

　　答案　A　[细节理解题。从第三段可知A项正确。]

　　4．We can learn from Suvorov's words that ________.

　　A．it's hard for the astronauts to perform their tasks together

　　B．more experiments will be carried out for a real journey

　　C．the astronauts should learn to make decisions on their own

　　D．different cultures of the astronauts don't matter any more

　　答案　C　[细节理解题。从第五段可知答案为C。]

　　B

　　Today we tell you about some new understanding of why cutting the main branch of a plant or tree can lead to better development.

　　The findings are from researchers on two_continents.Professor Prezemyslaw Prusinkiewicz of the University of Calgary in Canada led the research with scientists from Britain and Sweden.Their study appears in the Proceedings of the National Academy of Sciences.

　　Researchers have known since the 1930s that the actively growing tip of a plant produces a hormone(荷尔蒙) called auxin(生长素)．This hormone flows down the main stem.Scientists say the auxin has an indirect effect on buds(芽) on the side of the stem to prevent branching.

　　These buds themselves also produce auxin.The research suggests that to grow，they have to be able to export the hormone into the main stem.But the flow from the stem tip prevents them from doing this.The researchers wanted to find out how this blocking happens.

【（全国通用）2014届高考英语一轮单元复习 限时强化训练四】相关文章：

★ 2014届高考英语一轮复习课时作业(十二)必修2Module 6《Films and TV Programmes》（外研版）

★ （全国通用）2014届高考英语一轮单元复习 限时强化训练十

★ 2014届高考英语一轮复习课时作业(八)必修2Module 2《No Drugs》（外研版）

★ 天津市武清区杨村第四中学2016届高考英语一轮复习语法专题六《定语从句》课件外研版

★ 【浙江专用】2014届高考英语一轮复习课时作业(一)必修1Unit 1《Friendship》

★ （全国通用）2014届高考英语一轮单元复习 限时强化训练九

★ 2016年高考英语第一轮复习要知己知彼

★ 2014届高考英语一轮复习课时作业(三十三)选修6Module 3《Music》（外研版）

★ 2014届高考英语一轮复习必修5参考答案（外研版）

★ （全国通用）2014届高考英语一轮单元复习 限时强化训练二