infinitives - Why do 'get' and 'have' work similarly in 'get/have sth done" but differently in 'get sb to do sth' and 'have sb do sth'

Why do 'get' and 'have' work similarly in

I got/had my car repaired.

but differently – that is are not complemented in the same way although they still mean the same – in

I got someone to repair my car.

and

I had someone repair my car.

Answer

The verbs 'get' and 'have' are not completed in the same way, whether in an active sentence or in a passive one: it only looks as if they work the same way in a passive phrase like 'get/have something done', only looks.

Get:

• I got someone to repair my car. (active phrase)


• *I got my car to be repaired by someone. (passive phrase)


• I got my car repaired. (simplified passive phrase, 'to be' dropped)

Have:

• I had someone repair my car. (active phrase)


• *I had my car be repaired by someone. (passive phrase)


• I had my car repaired. (simplified passive phrase, 'be' dropped)

So it is only the simplified sentences which give the – mistaken – impression that 'get' and 'have' work the same way. Of course, the middle sentence in each case, even if it can be re-constructed, is not used.

Simplifications 'complicate' the task of learners of English, because they make it look as if something one has just learnt does not apply – here, 'get sb to do sth' but 'have sb do sth'- as if English were an endless list of exceptions rather than a language obeying a large but limited set of rules one can hope to learn!