一、完形填空
从题中所给的 A、B、C、D 四个选项中选出能填入空白处的最佳选项。
China owns the world's most advanced (先进的) high-speed railway network that covers almost every major city in the country. Today, the country is trying to break its own speed with the new CR450 high-speed train.
The CR450 can reach an average speed of 400 kilometers per hour, and its top speed can even hit 453 km/h. the CR450 appeared, the fastest high-speed train in the world was China's CR400, which has an average speed of 350 km/h and has millions of passengers. When it is put into use, for example, the travel time from Beijing to Shanghai will be cut down to about two and a half hours, which takes four and a half hours at present.
"The most important thing is not to make the train run fast, to make it brake(制动) correctly and steadily, " Zhao Hongwei from the China Academy of Railway Sciences said. The standard is that the CR450 should have the same brake as the CR400, which is 6,500 meters, even though it travels a lot faster. Besides, CR450 can start braking more , taking only 1.7 seconds while the CR400 needs 2.3 seconds.
To improve the brake system, engineers did lots of tests that were to check the safety and stability(稳定)of the brakes. During the tests, the brake disc (制动盘) became hot, with temperatures rising up to 700℃. Its turned from black to red. All the changes were recorded, and the data was put into a smart system to build a digital model of the brake system for calculations.
a better brake system, the CR450 also has the same noise level as the CR400. What's more, it is 12 percent lighter and uses 20 percent less energy-consuming, which makes it more environmentally friendly.
()1. A. reason B. record C. research D. result
()2. A. After B. Before C. When D. Since
()3. A. served B. surprised C. brought D. set
()4. A. and B. but C. or D. so
()5. A. distance B. speed C. time D. quality
()6. A. quickly B. slowly C. narrowly D. clearly
()7. A. designed B. proved C. shut D. sorted
()8. A. hardly B. closely C. widely D. really
()9. A. color B. shape C. size D. material
()10. A. Besides B. Except C. Without D. Including

1. B 2. B
3. A serve意为“服务”，surprise意为“使……吃惊”，bring意为“带来”，set意为“设置”。结合语境“CR400 已服务了数百万名乘客”可知选A。
4. B 本句为固定句型not... but...，意为“不是……而是……”。
5. A
6. A 本句后半句对比了制动启动时间，“CR450 仅需1.7秒，而 CR400需要2.3秒”，说明 CR450 的制动启动速度更快，故选A。
7. A 句意为“工程师做了许多为检测制动器安全性和稳定性而设计的测试。”design 意为“设计”，故选A。
8. D
9. A 由后半句“from black to red（从黑色变成红色）”，可知是制动盘的颜色发生了变化，故选A。
10. A

【分析】
做完形填空需先通读全文把握主旨（本文介绍中国CR450高铁的性能），再逐空结合语境、词义辨析、固定搭配及上下文逻辑关系解题：1. 需选与“打破速度”搭配的名词；2. 需判断CR450出现前后的时间逻辑；3. 需选与“乘客”搭配的动词；4. 需识别固定句型；5. 需选与制动参数（6500米）相关的名词；6. 需对比制动启动的速度差异；7. 需选描述测试目的的动词；8. 需选修饰“hot”的副词；9. 需对应“from black to red”的名词；10. 需判断递进关系的介词。
【解析】
1. 考查名词词义辨析：break speed record是固定搭配，意为“打破速度记录”，A（原因）、C（研究）、D（结果）不符合，故选B。
2. 考查连词：后文提到CR400是当时最快的高铁，说明CR450出现前，A（在…之后）、C（当…时）、D（自从）不符合时间逻辑，故选B。
3. 考查动词词义：serve passengers意为“服务乘客”，B（使吃惊）、C（带来）、D（设置）不符合语境，故选A。
4. 考查固定句型：not...but...意为“不是…而是…”，符合句意“最重要的不是让列车跑得快，而是制动正确平稳”，故选B。
5. 考查名词词义：后文提到制动参数为6500米，说明是制动距离，B（速度）、C（时间）、D（质量）不符合，故选A。
6. 考查副词：后文对比CR450制动仅需1.7秒，CR400需2.3秒，说明CR450制动启动更快，B（慢地）、C（狭窄地）、D（清晰地）不符合，故选A。
7. 考查动词：be designed to do意为“被设计来做”，句意为“工程师做了许多为检测制动器安全性和稳定性而设计的测试”，B（证明）、C（关闭）、D（分类）不符合，故选A。
8. 考查副词：really hot意为“真的很热”，A（几乎不）、B（紧密地）、C（广泛地）不符合语境，故选D。
9. 考查名词：后文提到“from black to red”，说明是制动盘的颜色变化，B（形状）、C（尺寸）、D（材料）不符合，故选A。
10. 考查介词：Besides意为“除…之外（还有）”，符合递进关系“除了更好的制动系统，CR450还有和CR400一样的噪音水平”，B（除…之外（不包含））、C（没有）、D（包括）不符合，故选A。
【答案】
1.B 2.B 3.A 4.B 5.A 6.A 7.A 8.D 9.A 10.A
【知识点】
完形填空解题技巧、词义辨析、固定搭配
【点评】
本文为科技类完形填空，围绕中国新型高铁CR450展开，考查学生对词汇在语境中的运用能力，涉及时间逻辑、固定句型、词义辨析等考点，整体难度适中，适合中等水平学生练习。
【难度系数】
0.5