I am not a teacher.My English teacher tried to teach us the use of causative structures.
For that reason, he gave us these example
"Ken cut his hair once a year."
He said that this sentence could be changed into "Ken has his hair cut once a year."
I think that he did make a mistake on the first sentence, shouldn't it be "Ken cuts his hair once a year?"
The present tense would be cuts, but the past tense would be cut.
A) What happened to the fence?
B) Someone cut through it yesterday.
So there's nothing wrong with your teacher's sentence grammatically (although used to cut or would cut are better options (than just cut) if it is intended to have a past sense), but whether he intended to use the present or past tense is another issue.
and most importantly,he didn't state where did he has his hair cut. So the example could be confusing since we don't know whether he cut his hair on his own.
Well if it states that he cut his own hair the location isn't particulalry important: the main point is that he did it.
He pointed out that "Ken has eaten all the sushi." could be changed into "Ken has all the sushi eaten." ,which, I suppose, is mistaken considering the same reason.
Ken has all the sushi eaten is possible if Ken, for instance, often has lots of sushi left over, and rather than letting it go to waste he asks people to eat it; but it's a very strange sentence.
Is his really wrong in giving us such examples?
I don't think he is wrong. Just keep reading and practising; there's lots of useful information on causative constructions on the internet.
There are other useful examples. For instance none of your sentences specify an agent.
He had his computer fixed by Richard.
Thanks for answering my question.
Student or Learner