Translation of "Longest" in Chinese

My longest romantic relationship lasted four months.

我最长的爱情是四个月。

Where is the longest tunnel in Japan?

日本最长的隧道在哪里？

The Yangtze, at 6,380 km, is Asia's longest river.

长江是亚洲的最长江，6380公里。

The Mississippi is the longest river in the United States.

密西西比河是全美國最長的河。

Tom is the one that has been waiting the longest.

汤姆是等了最长时间的人。

This is the longest novel that I have ever read.

這是我讀過最長的一本小說。

The Amazon is the second longest river in the world after the Nile.

亞馬遜河的長度僅次於尼羅河，是世界第二長的河。