正确答案: B

四强雄蕊

题目：十字花科植物的雄蕊共有6条，其中外轮两条较短，内轮4条较长，成为( )。

解析：B

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举一反三的答案和解析：

[单选题]A great number of _______students said they were forced to practise the piano.

questioned

[单选题]If our sense of wonder relics totally on the world of make-believe. we will_______.

fail to appreciate the joy in our lives

[单选题]

trouble

[单选题]蕊喙是变态的( )。

柱头

[单选题]第二节 完形填空 (共20小题：每小题1.5分，满分30分) 请阅读下面短文，掌握其大意，然后从36~55各题所给的四个选项(A、

B、C和D． 中，选出最佳选项，并在答题卡上将该选项的标号涂黑。 Introduction to letters to Sam Dear Reader, Please allow me to tell you something before you read this book. When my （36） ,Sam,was born , my heart was filled with joy . I had been sitting in a wheelchair for 20 years before then ,and I have been （37） ill many times . So I wondered if I would have the （38） to tell Sam what I had （39） . For years I have been hosting a program on the 40 and writing articles for a magazine . Being （41） to move freely , I have learned to sit still and keep my heart （42） , exchanging thoughts with thousands of listeners and （43） . So when Sam was born .I （44） to tell him about school and fridship , romance and work , love and everything else . That how I started to write these （45） , I hope that Sam would 46 them sooner or later . However , that expectation （47） when Sam showed aigns of autism (自闭症) at the age of two , He had actually stopped talking before the discovery of the signs . He （48） to communicate with others , even the family members . That was （49） for me but didn’t stop me writing on . I realized that I even 50 now to tell him . I wanted him to （51） what it means to be “diffenet” from others , and learn how to fight against the misfortune he’ll （52） as I myself .. his grandfather ,did ,I just (53) if I could write all that I wanted to say in the rest of my life . Now . (54） the book has been pubhshed . I have been given the chance , Every chapter in the book is a letter to Sam: some about my life .and all about what it means to be a （55） . Daniel Gottlied 第36题：

grandson

[单选题]根部形成层开始出现时为( )。

条状

[单选题]做下列运动的物体，能当作质点处理的是

旋转中的风力发电机叶片

解析：ABC选项中对所研究的问题,物体各部分的运动情况不一样所以不能看作质点,D可以.

[单选题]44

there