There are numerous high buildings, heavy traffic, and dense population in modern cities.

现代都市到处高楼耸立，交通拥挤，人口稠密。

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I had to get used to the sounds of sirens, dogs, snowplows and the general low-level hiss of traffic, a contrast to the utter peace, stillness, silence, stars and dense sweet scent of the forest.

我不得不习惯警笛、家犬、除雪机的声音，还有一般而言轻微的车辆嘶嘶声。这一切与完全的和平、静止、宁静、星辰和森林浓浓的甜味形成了强烈的对比。

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With the rising of dense and cold high buildings in the city, happiness is being broken into pieces and drifting away in the congested traffic and the foul air.

随着城市里那些密集而冰冷的高楼大厦拔地而起，在拥堵的车流中，在污浊的空气里，人们的幸福正在一点点地破碎，飘零。

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The young inventor envisages PaveGen systems being used to power off-grid appliances such as public lighting, illuminated street maps and advertising, and to be installed in areas of dense human traffic such as city centers, underground stations and school corridors.

CNN: Green sidewalk makes electricity -- one footstep at a time

To address the crush, carriers are offloading data traffic from dense urban areas onto Wi-Fi networks, while also seeking out more spectrum.

FORBES: The Solution For The Bandwidth Shortage? Better Silicon Devices

The popularity of the City's scheme suggests that the advantages of traffic restriction in dense urban areas may have been underestimated in the past.

ECONOMIST: The music of the metropolis