1.Our subject of Felipe Alfau's second novel,published more

1.Our subject of Felipe Alfau's second novel,published more than 40 years after it "has been" written,is the illusory nature of the passage of time.
文中的has been是错误的...请问正确的用法是什么?为什么这么用?为什么“has been”是错误的~
2.Along the curve of islands known as the Florida Keys lies a reef of living coral,the only one of "a kind" in the continental United States.
文中“a kind"是错误的,请问正确的用法是什么?为什么这么用?
关于机械尘封记忆...对于第一个，published more than 40 years after it () written...这里after引导的“主句”不是用的是一般过去式(be published)麽?如果我们想强调时间观念的话，用过去完成时会不会更准确呢(had been)？