double pair couple用法区别

double
（形容词）
Twice as much in size, strength, number, or amount:
两倍的，双倍的：大小、力量或数量上两倍的：
a double dose.
两倍的剂量
Composed of two like parts:
双层的：两个相同部分组成的双层的：
double doors.
双层门

pair
n.（名词）
【复数】 pair 或 pairs 缩写 pr.
Two corresponding persons or items, similar in form or function and matched or associated:
一对：相对应的两人或物，在样式或功能上相似并相配或相联系：
a pair of shoes.
一双鞋
One object composed of two joined, similar parts that are dependent upon each other:
一副：由相互依存的两个相连或类似部分组成的物件：
a pair of pliers.
一把钳子

couple
n.（名词）
Two items of the same kind; a pair.
一对，一双：同一种类的两件；一对
Something that joins or connects two things together; a link.
连接物：把两件东西连接在一起的东西；连接物
(used with a sing. or pl. verb)
（与单数或复数动词连用）
Two people united, as by betrothal or marriage.
夫妻，情侣：通过订婚或婚姻结合在一起的两个人
Two people together.
一对：在一起的两个人
Informal A few; several:
【非正式用语】 数个；几个：
a couple of days.
几天