"卡伦看上去很老,不是吗?" 是对的.这是个倒装的强调句.也可以翻译成:"卡伦看上去不是很老吗!" 所以才有后面顺理成章的
"是的(是很老),谁说不是呢!"(She does (look old),doesn't she!).
如果第一句是"不显老"的意思,回答表示同意就应该是:
She doesn't (look old).(她不显老.) 而且第一句得改成:
Karen Marsh doesn't look old!