第四的英語單詞怎么寫

　　例句：

　　1、He himself had only finished the fourth grade.

　　他自己只上完四年級。

　　2、What was that fourth priority, sir?

　　先后次序的第四條是什么，長官？

　　3、They hit pay dirt on the fourth day.

　　第四天，他們就發現了苗頭。

　　4、A fourth model may be tested for flutter speed.

　　第四個模型可用來進行顫振試驗。

　　5、Marry stood me up last night, and it was the fourth time.

　　瑪麗昨夜又失約了，這已是第四次了。