看看 / 看一看 / 看了看【kànkan / kàn yi kàn / kàn le kàn】

Saying a verb twice makes the action brief and relaxed: you do it a little, or give it a try. The second syllable is unstressed.

Like 一下, the doubled verb softens a request or a suggestion.

看一看

A one-syllable verb can take 一 in the middle. It means the same and sounds a touch more deliberate.

看了看 for something done

For an action that has happened, 了 goes in the middle. It doesn't go at the end.

• × 他看看了手表 → 他看了看手表

Two-syllable verbs

A two-syllable verb doubles whole, as ABAB: 休息休息, 介绍介绍. Splitting it into AABB is the adjective pattern and is wrong for verbs.

• × 休休息息 → 休息休息

A verb with a built-in object, such as 散步 or 聊天, doubles only the verb part: 散散步, 聊聊天.

What doesn't double

The doubled verb is a short, casual action, so it doesn't sit with 在 for something in progress, or with 一下 on top.

• × 我在看看书 → 我在看书
• × 你看看一下 → 你看看 / 你看一下

Verbs that aren't actions, such as 是, 有, 在 and 喜欢, don't double at all.