You use double before a singular noun to refer to two things of the same type that occur together, or that are connected in some way.
成对的
...bed and breakfast for $180 for two people in a double room. …
给两个人共用一个双人间的价格为$180的住宿加早餐。
When something doubles or when you double it, it becomes twice as great in number, amount, or size.
使加倍; 翻倍
"Give me a whisky," Debilly said to Francis. "Make it a double." “
给我来杯威士忌,”德比利对弗朗西斯说。“要双份的。”
If you are seeing double, there is something wrong with your eyes, and you can see two images instead of one.
看到重影
字母 W 的读音就是“double u”,意为两个 u 构成 w .