根据下列短文内容，在短文后的空格处填上一个恰当的词，使短文完整、通顺。

      Big schoolbags have been a serious problem for students   1   a long time. Maybe your schoolbags is too 

  2   to carry, and it troubles you a lot when you want to find a book out to read. Now an e-textbook will   3   

you. 

        4   is said that e-textbooks are going to be used in Chinese middle schools. An e-textbook , in fact, is a

small computer. It is much lighter than a usual schoolbag and easy to carry.   5   it is as small as a book, it can

hold all the materials. The students can read the text page by page   6   the screen,   7   notes with the pointer

(屏写笔). And even "hand in" their   8   to their teachers by sending-emails.

      Some people say e-textbooks are good, but some say they may be   9   for the students' eyes.   10   do you

think of it?

1.                 2.                 3.                   4.                 5.                

6.                 7.                 8.                   9.                 10.             

交流滤波器处于高压的电容器组一般布置为（）型结构。

A.D

B.E

C.L

D.H