There are many old people and many families with young children living here.

这里是there be句型后面的独立结构的典型用法。
这个句子中已经有了谓语are，其实是一个倒装句，真正的主语是many old people and many families with young children， 一个简单句中不能有两个谓语存在，所以必须处理成非谓语形式。

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