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问题 单项选择题

原核动物与细菌的区别是（）。

A.原核动物有细胞膜，细菌没有

B.原核动物有细胞质，细菌没有

C.原核动物有核糖体，细菌没有

D.原核动物有细胞核，细菌没有

答案

参考答案：D

改错题

改错，下列各句均有一处错误，请找出并改正。

1. — Whose pen is this? —It’s her. 

              A               B         C   D             ( ) __    ___

2. They don’t have any classes in Saturdays.

               A             B              C      D      ( ) ____       

3. He enjoys swiming in the river in summer. 

              A        B      C              D            ( ) _____     

4. — Can you swim? — No, I’m not.

           A            B           C       D             ( ) _____     

5. My friend Tina is thirteen year old 

          A          B  C                  D              ( ) _____    

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单项选择题

When experiencing heavy winds，you should reef sails to（）.

A.bring the sails parallel to the wind

B.reduce sail area exposed to the wind

C.allow the sails to catch more wind

D.remove all tension on the main and jib sheets
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