These TV sets have gone up in quality, but have not risen in pric_英语解答

These TV sets have gone up in quality, but have not risen in price.
but,后主语为什么可以省略

人气：142 ℃　时间：2020-02-06 06:10:04

解答

因为前后的主语一致,所以可以省略
如果不一致,省略会引起歧义