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26. ---Will Tony come to the party tonight?

  ---I’m not sure. He _______stay at home preparing for the coming exam.

A. must    B. might    C. can    D. need

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25.The house I grew up _______ has been pulled down and replaced by a hospital.

  A. in it    B. in    C. in that    D. in which

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24. ______ the project in time, the staff have been working at weekends since last summer.

  A. Completing   B. Having completed  C. To have completed  D. To complete

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23. ---Why do you keep looking back?

  ---I have a feeling that we _______.

  A. were followed  B. have been followed  C. are being followed  D. are following

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22. Tom is determined to go on _______ voyage across the Atlantic Ocean again although he is still in ______ bad condition.

   A. the; the   B. a; the    C. the; a    D. a; /

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第一节 单项填空(共15小题; 每小题1分,满分15分)

21. ---The meeting’s been put off until next week.

  ---Sorry, ______. Could you say it again?

   A. I didn’t mean that   B. I didn’t know  C. I didn’t take it  D. I didn’t get it

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50、(10分)其家庭中有的成员患丙种遗传病(设显性基因为B,隐性基因为b),有的成员患丁种遗传病(设显性基因为A,隐性基因为a),见下面系谱图现已查明Ⅱ一6不携带致病基因。

(1)丙种遗传病的致病基因位于     染色体上,丁种病的基因位于    染色体上。

(2)写出下列两个体的基因型:Ⅲ一8      ,Ⅲ一9         

(3)若Ⅲ一8和Ⅲ一9婚配,子女中患丙或丁一种遗传病的概率为          

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49、(8分)苹果的红果皮(A)和绿果皮(a)为一对相对性状,圆形果(R)对扁型果(r)是另一对相对性状,两对相对性状遵循基因的自由组合定律,假若现有红圆、红扁、绿圆三个纯系品种,请设计一个培育绿色扁形果的杂交试验:

(1)选择杂交的两个亲本P1 、P2应是               

(2)P1×P2   F1,然后如何处理?                     

(3)能否直接从F2中选出所培育的品种?请说明理由。­­­­­­­­­­­­­­­­­­­­­­­­­­­­

                                  

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