a recent national study of the public schools shows

有的意思
there is now one microcomputer for every thirty-two pupils,four times as many as there （were） four years ago
现在每三十二名学生有一个微型计算机是四年前的四倍
再问： 为什么不用was 呢？
再答： 与many一致
再问： 是指as many as there were four microcomputer for every thirty-two pupils?怪怪的
再答： 应该是a microcomputer for every one hundred twenty-eight pupil
再问： 可是前面的thirty-two也是用is啊
再答： 这个问题我也有疑问，我也解释不清了。