1. But optimists see the current problems of expanding cities as merely part of an evolutionary process.
    但是乐观主义者认为，现在城市膨胀造成的问题只不过是发展过程中的自然现象。

2. Yes, the earth's resources are not infinite; natural areas are being destroyed; the number of plant and animal species is declining; consumption of resources is expanding.
    是的，地球的资源不是无限的，自然界在遭受破坏，动植物的物种数目在减少，而资源的消耗却在增加。

3. Job opportunities for students are expanding rapidly and more people of all ages are becoming aware of online learning that allows them to study at home.
    随着学生就业机会的迅速增多，越来越多不同年龄层的人开始意识到了这种在家中就学的网上学习方式。

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