我看不懂这个笑话啊，求助！

裤子的腰口是一个 当然就是单数叻 下面 是两个裤腿 就是复数叻1.被,由
The homework was assigned by the teacher.
这些家庭作业是老师布置的。
2.靠,用,通过
They crossed the river by ferry.
他们乘渡船过了河。
3.经由;沿
Ellen flew to Chicago by way of Minneapolis.
艾伦经由明尼阿波利斯飞往芝加哥。
4.在...旁边,靠近;在...手边
I haven't got any money by me.
我身边没有带钱。
5.不迟于;在...之前
We had to get there by evening.
我们必须在夜晚前抵达那里。
6.根据,按照
How do you know he didn't act by the rules?
你怎么知道他没有按规定行事?
7.(表程度)相差
He missed the bus by three minutes.
他晚了三分钟没赶上那班公车。
8.凭,对...(发誓)
I swear by God!
我对上帝发誓!
9.(乘除法上)以...,用...(乘或除)
Nine divided by three makes three.
九除以三得三。
10.以...计,按
You'll be paid by the hour.
你的工资将按时计酬。
11.在...的时候
He had to sleep by day and work by night.
他只好白天睡觉,晚上工作。
12.就...来说,关于
Philip is a doctor by profession.
菲利浦的职业是医生。
13.(表连续或反复)逐个;逐批
The teacher explained the text sentence by sentence.
教师逐句讲解了这篇课文。
14.由于
She took my umbrella by mistake.
她误拿了我的伞。

副词 ad.

1.经过;过去
A truck went by.
一辆卡车开过。
2.在旁边
When I filled out the form she was standing by all the time.
我填写表格时,她一直站在我身旁。
3.(放)在一边
They put money by for later use.
他们储存钱以备将来使用。
4.【美】【口】到(或进入)某人的家
Please come by and have dinner with us.
请到我家来一起吃晚饭。

b.y.
缩写词 abbr.

1.=billion years 十亿年

by-
前缀 pref.

1.表示"附近","邻近"
2.表示"侧","边"
3.表示"次要的"

那就是别人的思想太XE了
个人听到这个笑话的脑内第一反应不一样
说明他们真的太邪恶了。。

SM是性虐待症，sadomasochism的缩写
引申为 变态行为（色魔）
————————————————————————
是你自己的思想太邪恶了。。。

意思就是上面是一个口是单数，下面2条裤腿有2个口是复数

DY是荡漾
顺便告诉你
邪恶是XE

上面只有一个筒，下面两只裤腿两个筒啊
一个是单，两个就是双咯。。
不过这个笑话实在已经称不上是笑话了、、太老了而且没有笑点。。。。。

我看了半天怎么就没看懂 你们在说什么呢