write down

Separable

The object can go between the verb and the particle: turn the light off, or turn off the light. When the object is a pronoun it must go in the middle: turn it off, never turn off it.

The particle: down

This verb belongs to the group ‘writing it down’.

Others in the group: note down, jot down.

Practise it

Add it to your daily practice or see every verb with down.

Further reading: write down on Wiktionary (CC BY-SA).