九日的英文：
ninth

What did the suspect do on July ninth?
嫌疑犯在七月九日做了什么事情?

Date of publishing the result of an examination: July 9th, 2004 Friday.
放榜日期:九十三年七月九日(星期五)。

I'd like to book a flight to Munich for the ninth of June, please.
我想订一张六月九日飞慕尼黑的机票。

Here is a letter adapted from DEaR abbY, Philadelphia Bulletin, March 9,1973.
这里摘登一封'亲爱的爱毕'的回信，刊登在一九七三年三月九日的'费城公报'上。

The answer is ten to the ninth power.
答案是10的9次幂。

A chord consisting of a root with its third, seventh, and ninth.
九和弦由第三、第七和第九三个基础音组成的和弦

The score stood tied in the Bottom of the ninth inning.
在第九回合下半局比分持平

The Fourth Session of the Ninth National People's Congress
九届全国人大四次会议

Now the Yangtze River has been bridged for the ninth time.
现在扬子江上已架设了9座桥梁。