The population of the world has more than doubled in the past ten years.
这里more than 后面的doubled是形容词呢,还是说是has doubled,然后more than 是相当于副词来修饰doubled这个过去分词?
因为有 as expected,than usual 这些后面都跟的形容词,所以我认为是doubled是形容词,但是如果真是这样,more than 是不是也可以改成as many as doubled?