问题 问答题 简答题

如何进行氧气管道的吹洗?

答案

参考答案:

氧气管道强度试验和严密性试验合格后,即可进行吹洗工作。吹洗应采用压缩空气(或氮气)和氧气分别进行。管道先利用压缩空气或氮气吹洗,其要求首先是压缩空气和氧气不能含油,气流流速不小于20米/秒。

阅读理解

B

It is surprising that eating three meals a day ─ breakfast, lunch, and dinner ─ has been a custom only since 1890. Before this time, they only had two meals a day ─ breakfast and dinner.

In the 16th century, breakfast was only to break one's fast (随便吃一点). But 200 years later it had become a large meal , not just for family, but for numbers of guests as well. It was a social event, It began at 10 a.m. and lasted until l p.m.. Then breakfast began to be less popular. It became , instead, a lighter meal and was taken at a much earlier hour. By 1850 it had been pushed hack to 8 a.m.. and became a family meal.

Dinner, however, went the other way. In the 16th century it was eaten at 11 a.m.. Years later, it had moved to the early afternoon, then to 5 p. m.. By 1850 dinner time had reached 7 p.m. Lunch is a recent idea. It first appeared as a snack to fill the gap between breakfast and dinner.

59. English people did not have lunch _________.

A. before 1890    B. after 1890        C. after 16th century   D. by 1850

60. "Dinner, however, went the other way" means _________.

A. Dinner didn't go there with breakfast    B. Dinner took the same way with breakfast

C. Dinner is different from breakfast        D. Dinner is the same with breakfast

61. Lunch has been served since the end of the ________ century.

A. seventeenth    B. eighteenth        C. sixteenth           D. nineteenth

62. The selection is mostly concerned with _________.

A. what people eat for breakfast         B. what people eat for dinner

C. the history of supper                D. the history of breakfast

63. The selection leads the reader to believe that __________.

A. our custom of meals is based on English custom

B. before 1890 people also ate three meals a day

C. breakfast is the most important meal for us

D. the body can adjust to two or three meals a day      

判断题