that's a sensational news,isn't it/that's sensational news,isn't

Question

以上两个句子都对吗? 为什么有的加a有的不加a 哪位大神帮帮忙

Answer 1

【都对】因为：
news不可数时是指新闻，可数时是指消息。a sensational news就是一个轰动一时的消息，sensational news就是轰动一时的新闻

sensational
英 [sen'seɪʃ(ə)n(ə)l] 美 [sɛn'seʃənl]

adj. 轰动的；耸人听闻的；非常好的；使人感动的
N-UNCOUNT News is information about a recently changed situation or a recent event. 消息
例：
We waited and waited for news of him.
我们等啊等啊，等他的消息。
例：
They still haven't had any news about when they'll be able to go home.
他们仍然没有得到任何关于他们何时才能回家的消息。
2.
N-UNCOUNT News is information that is published in newspapers and broadcast on radio and television about recent events in the country or world or in a particular area of activity. 新闻 [also 'the' N]
例：
Foreign News is on page 16.
国外新闻在第16版。
例：
Those are some of the top stories in the news.
那是新闻中的一些顶级报道。
3.
N-SING The news is a television or radio broadcast which consists of information about recent events in the country or the world. (电视、电台等的) 新闻广播
例：
I heard all about the bombs on the news.
我从新闻广播里听到了关于炸弹的所有消息。
4.
N-UNCOUNT If you say that someone or something is news, you mean that they are considered to be interesting and important at the moment, and that people want to hear about them on the radio and television and in newspapers. 新闻人物; 新闻事件 [非正式]
例：
A murder was big news.
谋杀案是大新闻。

Answer 2

因题干条件不完整，缺已知条件，不能正常作答。