The causative is a common structure in English. It is used when one thing or person causes another thing or person to do something.

There are two basic causative structures. One is like an active, and the other is like a passive. These examples use the causative verb "have":

I had John fix the car.

(I arranged for the car to be fixed by John -- I caused him to fix it.)

I had the car fixed.

(I arranged for the car to be fixed by someone. We don't know who, so this is like a passive.)

The active causative structure

This is the basic structure of the active form, along with some more examples:
 

Subject	Causative verb	Agent	Action verb	Object
Susan	had	her brother	do	her homework.
The police	had	the suspect	stop	his car.
We	had	the carpenter	fix	our window.

The passive causative structure

In the passive form, there is usually no agent. The action verb is in the past participle, and the object comes before it:

Subject	Causative verb	Object	Action verb
We	had	our door	fixed.
Yukiko	had	her hair	cut.
Sanjay	had	the windows	cleaned.

Other causative verbs

All the examples above use the causative verb "have". However, many other verbs can be used in causatives. In the active form, som of these verbs require the action verb to have "to" before it. These are some examples of the most common causative verbs.

Verb	Meaning	Form of Action Verb	Examples
make	force, compel	plain form	The robbers made us lie on the floor. [No passive form]
get	same as "have"	"to" form	I got Jae Won to pick me up in the car. She got her hair cut.
let	allow	plain form	I'll let you borrow my bike. [No passive form]