登录
六、阅读理解。热点素材
It is widely known that China has the most advanced high - speed railway network in the world. Now, the country is breaking its own speed record with the CR450.
The CR450 can travel at 400 kilometres per hour on average, with a top speed hitting 453 km/h. Before this, the fastest high - speed train operating in a rail network in the world is China's CR400, which runs at 350 km/h on average.
Once put into use, for example, the CR450 will shorten the travel time from Beijing to Shanghai to just about two and a half hours, which takes at least four and a half hours at the moment.
"The key is not to make the train run fast but to have it brake (刹车) accurately (精准地) and steadily (平稳地), " Zhao Hongwei from the China Academy of Railway Sciences told CCTV News. The standard is that the CR450 should have the same brake distance as the CR400, which is 6,500 metres, even though it travels a lot faster. It can also start braking more quickly, taking just 1.7 seconds compared to 2.3 seconds needed for the CR400.
The engineers did lots of tests with the brakes to make the system better. In the tests, the brake disc (制动盘) got really hot, reaching temperatures of up to 700℃. Its colour changed from black to red. The changes were then recorded. All the data was saved in a smart system to make a digital model (数字模型) of the brake system for calculations (计算).
Apart from having a better braking system, the CR450 has the same noise level as the CR400. Moreover, it is 12 per cent lighter and 20 per cent less energy - consuming (耗能的), according to CCTV News. With all its advantages, people are getting excited about the train's debut (首次亮相).
(
A. 50 km/h
B. 100 km/h
C. 350 km/h
D. 450 km/h
(
A. Increasing the train's speed.
B. Making it brake accurately and steadily.
C. Having shorter braking distance.
D. Starting to brake in a shorter time.
(
A. is 0.6 seconds faster
B. is 0.6 seconds slower
C. is the same
D. is 1 second faster
(
A. How engineers cooled down the brake disc in a test.
B. What engineers did to improve the brake system.
C. How a digital model was used for calculations.
D. What differences the CR400 and the CR450 have in their brake systems.
It is widely known that China has the most advanced high - speed railway network in the world. Now, the country is breaking its own speed record with the CR450.
The CR450 can travel at 400 kilometres per hour on average, with a top speed hitting 453 km/h. Before this, the fastest high - speed train operating in a rail network in the world is China's CR400, which runs at 350 km/h on average.
Once put into use, for example, the CR450 will shorten the travel time from Beijing to Shanghai to just about two and a half hours, which takes at least four and a half hours at the moment.
"The key is not to make the train run fast but to have it brake (刹车) accurately (精准地) and steadily (平稳地), " Zhao Hongwei from the China Academy of Railway Sciences told CCTV News. The standard is that the CR450 should have the same brake distance as the CR400, which is 6,500 metres, even though it travels a lot faster. It can also start braking more quickly, taking just 1.7 seconds compared to 2.3 seconds needed for the CR400.
The engineers did lots of tests with the brakes to make the system better. In the tests, the brake disc (制动盘) got really hot, reaching temperatures of up to 700℃. Its colour changed from black to red. The changes were then recorded. All the data was saved in a smart system to make a digital model (数字模型) of the brake system for calculations (计算).
Apart from having a better braking system, the CR450 has the same noise level as the CR400. Moreover, it is 12 per cent lighter and 20 per cent less energy - consuming (耗能的), according to CCTV News. With all its advantages, people are getting excited about the train's debut (首次亮相).
(
A
)1. Compared to the CR400, the average speed of the CR450 increased by .A. 50 km/h
B. 100 km/h
C. 350 km/h
D. 450 km/h
(
B
)2. According to Zhao Hongwei, what is the "key" to the CR450?A. Increasing the train's speed.
B. Making it brake accurately and steadily.
C. Having shorter braking distance.
D. Starting to brake in a shorter time.
(
A
)3. Compared to the CR400, the braking time of the CR450 .A. is 0.6 seconds faster
B. is 0.6 seconds slower
C. is the same
D. is 1 second faster
(
B
)4. What is Paragraph 5 mainly about?A. How engineers cooled down the brake disc in a test.
B. What engineers did to improve the brake system.
C. How a digital model was used for calculations.
D. What differences the CR400 and the CR450 have in their brake systems.
答案
六、1. A 【点拨】根据文中信息可知，CR450 的平均速度为 400 km/h，而 CR400 的平均速度为 350 km/h。因此，CR450 相比 CR400 平均速度增加了 50 km/h。故选 A。
2. B 【点拨】根据第四段内容可知，CR450 的关键是要让它刹车精准且稳定。
3. A 【点拨】文中提到 CR450 的刹车时间只需要 1.7 秒，而 CR400 需要 2.3 秒，所以 CR450 比 CR400 快了 0.6 秒。
4. B 【点拨】第五段主要讲述了工程师们如何通过测试和记录数据来改进刹车系统，以及如何使用智能系统创建刹车系统的数字模型进行计算。
2. B 【点拨】根据第四段内容可知，CR450 的关键是要让它刹车精准且稳定。
3. A 【点拨】文中提到 CR450 的刹车时间只需要 1.7 秒，而 CR400 需要 2.3 秒，所以 CR450 比 CR400 快了 0.6 秒。
4. B 【点拨】第五段主要讲述了工程师们如何通过测试和记录数据来改进刹车系统，以及如何使用智能系统创建刹车系统的数字模型进行计算。
