it would be very hard for Andersen to realize his dreams as a play writer.
that引导宾语从句,所填部分为完整句子。
王子告诉安徒生:“演戏是一回事,写剧本则是另一回事。”他的意思是,安徒生要实现他成为一个剧作家的梦想是很难的。