问题
单项选择题
于球阀的优点，表述错误的一项是（）。
A、流体阻力小
B、机构简单、体积小、重量轻
C、操作方便，关闭迅速，从全开到全关只需旋转180°
D、可用于带悬浮固体颗粒的介质中是
答案
参考答案：C
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于球阀的优点，表述错误的一项是（）。
A、流体阻力小
B、机构简单、体积小、重量轻
C、操作方便，关闭迅速，从全开到全关只需旋转180°
D、可用于带悬浮固体颗粒的介质中是
参考答案：C
| 阅读下列短文，从每小题所给的四个选项（A、B、C和D）中，选出最佳选项。 |
| Strange thing happens to time when you travel. Because the earth is divided into twenty-four time zones one hour apart, you can have days with more or fewer than twenty-four hours, and weeks with more or fewer than seven days. If you make a five-day trip across the Atlantic Ocean, your ship enters a different time zone (时区) every day. As you enter each zone, the time changes the hour. Travelling west, you set your clock back; travelling east, you set it ahead. Each day of your trip has either twenty-five or twenty-three hours. If you travel by ship across the Pacific you cross the International Date Line. By agreement, this is the point where a new day begins. When you cross the line, you change your calendar the full day, backward or forward. Travelling east, today becomes yesterday; travelling west, it is tomorrow! |
| 1. The best title for this passage is . |
[ ] |
| A. A Trip Across the Atlantic B. How Time Changes Around the World C. Crossing the International Date Time D. How Time Zones Were Set up |
| 2. From the passage it seems true that the Atlantic Ocean . |
[ ] |
| A. is in one time zone B. is divided into twenty-four time zones C. is divided into five time zones D. cannot be crossed in five days |
[ ] |
| 3. The International Date Line is the name for . |
[ ] |
| A. the beginning of any new time zone B. the point where time change by one hour C. the point where a new day begins D. any time zone in the Pacific Ocean |
| 4. If you cross the ocean going east, you set your clock . |
[ ] |
| A. ahead one hour in each new time zone B. ahead one time for the whole trip C. back one full day for each one full day D. ahead by twenty-three hours |