世界上许多超级大城市都面临着严重的交通拥堵问题。

Many ___mega-cities around the world struggle with severe traffic congestion.

北京和上海这样的超大城市是全球商业和文化交流的重要枢纽。

Beijing and Shanghai are ___mega-cities that serve as vital hubs for global business and cultural exchange.

东京和横滨已经合并成一个拥有超过3000万居民的超级都市。

Tokyo and Yokohama have merged into a ___mega-city with over 30 million inhabitants.