watermelon
例句：（1）西瓜內紅外綠。
A watermelon is red inside and green outside.
（2）現在是伏天，西瓜正當令。
These are the dog days; watermelons are just in season.
（3）這西瓜好甜哪！
This watermelon is really sweet!
（4）都快冬天了，西瓜早就下市了。
It is almost winter and watermelons have long gone out of season.
西瓜[xī guā]
[watermelon] 壹種壹年生蔓生藤本植物,開淡黃色的花,葉有5-7個深裂片,為熱帶非洲原產,現已廣泛栽培
參考資料
吳光華.漢英大詞典.上海：上海譯文出版社，2010