原句是个省略句
A survey by Harris Interactive found Chicago is the most stressed city in the nation, (which is) followed (by) Houston, Boston, Los Angeles and San Diego.
不象,否则语法上(1)时态不一致;(2)两个句子只用逗号分开, 成run-on sentence.
A survey by Harris Interactive found Chicago is the most stressed city in the nation, (which is) followed Houston, Boston, Los Angeles and San Diego.
is - 现在时
followed - 过去时