There are three times as many grils as boys.求分析这句话主要是后面的as m

这是表示倍率的形式,我老师教的好像是 This is as tall a tree as that one.
这里注意位置as+ adj.+n.as名词做单数时的用法不能丢冠词这里是个考点.
总之就是要举一反三,其实你那个例句由于是复数反而容易忽视冠词,要小心.