"等等" (děng děng), or simply "等", has the same meaning as “and so on” or “etc.” in English. Both are placed after a series of items (the list of which generally exceeds two items).

Structure:
The basic structure is easy. Just make a list of things, and add 等 or 等等 to the end of the list. It's the same as in English when we use "etc." at the end of a list.

Examples:

Wǒ xǐhuɑn kànshū、ɡuànɡ jiē、shuìjiào děnɡ.
我 喜欢 看 书、逛 街、睡觉 等。
I like to read books, window-shop, sleep etc.

Xīɡuā、bōluó、pínɡɡuǒ、pútɑo děnɡděnɡ, dōu shì wǒ xǐhuɑn de shuíɡuǒ.
西瓜、菠萝、苹果、葡萄 等等，都 是 我 喜欢 的 水果。
Watermelons, pineapples, apples, grapes and so on， are all the fruits that I like.