用双滤膜法测量环境空气中氡浓度时，每半年要用标准氡室对测量装置刻度一次。

At present we are living in a good age. Therefore, there are still a

small number of people who don't act responsibly. His bad behaviors are

out of place in our civilizing society. For an example, some people often

risk their lives to disobey traffic rules. Littering is still a seriously problem.

Some people are often seen spit in public places. Bad still, it is common to

find silly things written by some tourists in scenic spots.

To my opinion, everyone should learn to become a responsible citizen.

We must aware that everything we did in public places will affect others and

we should break our bad habits. As long as we obey the rule in every field and

are filled with care and love, our world will become better.

工件坐标系的Z轴一般与主轴轴线重合，X轴随（）原点位置不同而异。

A.工件

B.机床

C.刀具

D.坐标

阿米巴痢疾病人留取粪便标本的容器是（）

A.硬纸盒

B.玻璃瓶

C.蜡纸盒

D.无菌容器

E.加温容器

区域经济落后地区的资金缺乏是一个普遍的现象。

船舶航向稳定性与其长宽比L／B和方型系数有关：（）.

A.长宽比L／B越大、方型系数越大，航向稳定性越好

B.长宽比L／B越小、方型系数越小，航向稳定性越好

C.长宽比L／B越大、方型系数越小，航向稳定性越好

D.长宽比L／B越小、方型系数越大，航向稳定性越好