问题 问答题 简答题

为什么单元制一级除盐系统中,阴床先失效时,除盐水电导率先下后上升?

答案

参考答案:

当阴床失效后,首先放出硅酸根,而硅酸根和阳床出水中残留的钠离子生成硅酸钠,而硅酸钠是一种弱电解质,其电导率相应要小些。所以当阴床失效初步放硅时,会使阴床出水电导率短时间内下降。但随着阴床的进一步失效,大量阴离子放出后形成盐酸、硫酸,阴床出水电导率就很快上升。

填空题

阅读填空。

(A. held  B. enjoy  C. off  D. whole  E. well  F. airports

 G. stay up  H. comes  I. get  J. for  K. all  L. stops )

                                                                       Spring Festival

     The Spring Festival is the most important festival for the Chinese people and is when all family

members    1    together, just like Christmas in the West. All people living away from home go back,

    2    railway stations and long-distance (长途) bus stations are crowded with home returnees

(回家的人).

      The most important days are Spring Festival Eve and the first three days. The Chinese people now

have seven days    3    to celebrate the festival and have a rest.

     There are many customs (习俗) during the Spring Festival. The 23rd day of the 12th lunar month

is called "Xiao Nian". At this time, most families make delicious food to    4    themselves.

      After that, people begin preparing   5    the coming New Year. This is called "Seeing the New

Year in (迎新年)".

     Store owners are busy because everybody goes out to buy things for the New Year. Include oil, ice…

new clothes and shoes for the children as    6    as gifts for the elderly (老人), friends and relatives.

     Before the New Year    7   , the people completely clean the indoors and outdoors of their homes.

     Then people begin decorating their clean rooms. The Chinese character (汉字) "fu" (meaning blessing

or happiness) is a must.

     The great important time is Spring Festival Eve. At that time, all family members eat dinner together.

The meal is more luxurious (丰盛) than usual. After the dinner, the    8    family will sit together, chatting

and watching TV. In recent years, the Spring Festival party broad on CCTV is essential (基本的)

entertainment (娱乐). According to custom, each family will    9    to see the New Year in.

      A series of activities such as lion dancing, dragon lantern dancing, lantern festivals and temple

fairs (庙会) will be    10    for days. The Spring Festival then comes to an end when the Lantern

Festival (元宵节) is finished.

1._____ 2._____ 3._____ 4._____ 5._____

6._____ 7._____ 8._____ 9._____ 10._____

单项选择题