more than three times as many independent institutions of higher education charge tuition and fees of under $8,000 a year as those charging over $16,000.
谓语动词是charge且只能是charge,那么就可变成 as many independent institutions of higher education as those charging over $16,000 charge tuition and fees of under $8,000 a year。
是不是很顺?把as those charging 後置唯一的原因就是直接放前面charging over 16000让人搞不清在说什么吧,放后面就清楚啦。