at least 为何 at least是副词 ,还有别的搭配类似于这样的吗?

at least 为何 at least是副词 ,还有别的搭配类似于这样的吗? She must be at least forty.请问其中的at least是副词,还是介词短语,用来修饰哪个词? at least的同义词 at least 的用法 at least的用法 at least at least中的least是什么词性,是形容词还是副词啊? at least ,at most ,这里的AT 是表示什么? at most &at least at least的同义短语 at least twice 和 twice at least at least与at the least