问题 选择题

已知地球同步卫星离地面的高度约为地球半径的6 倍。若某行星的平均密度为地球平均密度的一半,它的同步卫星距其表面的高度是其半径的2.5 倍,则该行星的自转周期约为[ ]

A.6小时        

B. 12小时        

C. 24小时      

D. 36小时

答案

答案:B

改错题

此行多一个词:把多余的词用斜线(\)划掉,在该行右边横线上写出该词,并用斜线划掉。

此行缺一个词:在缺词处加一个漏字符号(∧),在该行右边横线上写出应加的单词。

此行错一个词:在错词下画一横线,在该行右边横线上写出改正后的单词。

注意:原行没有错误的不要改。

My classmate,Joseph,is at present in hospital                                                         

with a breaking leg.He was walking to school the other                                              1.         

day when he let a bicycle ran right into him.He never                                                2.         

watches where he is going,so he often gets into the trouble.                                     3.         

But he is having a nice time there.He has a comfortable                                             4.         

room,patiently nurses,and a great deal of time to read.                                                 5.         

Some friends of his go to see him every day,they take him                                         6.         

lots of good book and fresh fruit.He is not losing any time                                                7.         

from school because he is busy study what he has                                                               8.         

missed in class.The doctor says he is recovering fast than                                       9.         

expected and will be out of hospital a few weeks.                                                      10.         

判断题