什么是除滤机理中的拦截作用？

()是电焊作业人员常见的职业性眼外伤，主要由电弧光照射、紫外线辐射引起。

A.白内障

B.红眼病

C.电光性眼炎

下列指标中属于时点指标的有（）

A、企业数

B、在册职工人数

C、某种商品的销售量

D、某地区2004年人口数

E、某种产品的产量

Questions 9-13

·You will hear a passage about "Surviving Cultural Shock".
·For questions 9-13, choose from the list A-F the five stages of cultural shock.
·Use the letters only once. There is one extra letter, which you do not need to use.
9. Stage 1 ______
10. Stage 2 ______
11. Stage 3 ______
12. Stage 4 ______
13. Stage 5 ______
A. The Re-entry
B. The Rejection
C. The Acceptance
D. The Honeymoon
E. The Regression
F. The Non-Party

Questions 9-13

·You will hear a passage about "Surviving Cultural Shock".
·For questions 9-13, choose from the list A-F the five stages of cultural shock.
·Use the letters only once. There is one extra letter, which you do not need to use.
9. Stage 1 ______
10. Stage 2 ______
11. Stage 3 ______
12. Stage 4 ______
13. Stage 5 ______
A. The Re-entry
B. The Rejection
C. The Acceptance
D. The Honeymoon
E. The Regression
F. The Non-Party

道氏理论将价格的波动分为超级趋势、主要趋势、次要趋势、短暂趋势四种。( )

下列（）不是曳引钢丝绳芯的作用。

A.摩擦曳引轮产生的曳引力

B.支撑绳股

C.固定绳股

D.储存润滑油