highway：我看有个high，以为是高速公路，实际却是一般的公路。
freeway：免费的路，自然是一般的公路了，实际却是高速公路，难道国外的高速路不收费吗？
green joke：黄色笑话。也有说blue joke， dirty joke的。

since we talked about the blue joke,so I'll show you one:

A husband said to his wife, "I will take a photo of your breasts and frame it ."
The wife said to her husband, "I will take a photo of your penisss and enlarge it."


Q:what is the strongest muscle?
A:the tongue—it can raise a woman’s hips.
Q:what is the lightest muscle?
A:the penis—it can be raised by a tongue.