问题
单项选择题
( )应采用对焊法兰的方式。
A．在设计压力不大于1.6MPa、设计温度不大于200℃的低压流体输送用焊接钢管上
B．设计温度300℃及以下且PN≤2.5MPa的管道
C．设计温度大于300℃或PN≥4.0MPa的管道
D．设计温度大于2000℃或PN≥6.3MPa的管道
答案
参考答案：C
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( )应采用对焊法兰的方式。
A．在设计压力不大于1.6MPa、设计温度不大于200℃的低压流体输送用焊接钢管上
B．设计温度300℃及以下且PN≤2.5MPa的管道
C．设计温度大于300℃或PN≥4.0MPa的管道
D．设计温度大于2000℃或PN≥6.3MPa的管道
参考答案：C
Teenagers in England do many of the same thi  ngs as children in America do . They enjoy sending messages on their mobile phones and they also like swimming , listening to the latest music , watching TV and surfing the Internet .How do teenagers in England spend their free time and holidays ? Let’s follow Sally , a British teenager , and spend five days with her during her school holiday .
A. In the morning . B. In the afternoon . C. At lunch time . D. In the evening . 2. Which of the foll  owing things did Sally do on Day Four ?A. She went swimming . B. She went out for breakfast . C. She read books . D. She went shopping . 3. How many times did Sally and her mother meet their friends during the five days ? A. Once . B. Twice . C. Three times . D. Four times . 4. According to the passage , it can be inferred that__________. A. a park is the best place to meet a friend B. parents shouln’t leave teenagers alone at home C. teenagers don’t usually do their homework during their school holidays D. surfing the Internet has become an important part of teenagers’ lives |
s and went swimming together . Later , they wnet shopping for clothes and books , and had dinner in a restaurant .