自从他们来中国后,参观了许多城市。用英文怎么说

They have visited many cities thin them came to China.相信我，我是英语专业的。

Ever since they came to China and visited many cities

Ever since they came to China and visited many cities

绝对准确！

They have visited many cities since they came to/arrived in/reach China.

相信我 我是研究生

Since they arrived China they have visited many cities .