maxiewawa wrote:I've got a list of transitive verbs and their intransitive equivalents, from my 'Teach Yourself' book.
okiru/okosu, ochiru/orosu wareru/waru, kowareru/kowasu, aku/akeru, shimaru/shimeru, naoru/naosu
I know the difference between intransitive and transitive verbs, but I can't see how they are formed.
Do I have to just memorise all of these pairs, or is there some kind of construction that I am missing?
You can't really learn to form them, but you can learn to recognize them.
If it ends in "aru", it is usually intransitive.
If it ends in "eru", it is usually transitive, unless it ends in "reru", when it is usually intransitive.
If it ends in "su", it is usually transitive.
If it ends in "iru", there doesn't seem to be a rule, but IMO, it's usually *transitive*. (Although the examples you've given above are exceptions.)
There do seem to be some basic formation rules, but I'm not sure how useful/practical it would be for you to memorize these.
"-aru" intrans. verbs usually have a "-eru" trans. partner.
"-reru" intrans. verbs usually have a "-ru" or "-su" trans. partner.
"-iru" trans. verbs I haven't thought enough about to tell you. I think many of them are verbs that have a transitive form only. Like 用いる.
The rare "-iru" intrans. verbs usually have a "-osu" trans. partner.
"-keru" trans. verbs usually have a "-ku" intrans. partner; "-beru" trans. verbs usually have a "-bu" intrans. partner, etc.
You actually could have kinda figured out all of those rules by yourself, from the examples that you posted above.
Tetsudatte kudasai! (Please help me!) Tetsuderu ni shitai! (I want to be helped!)(I'm not sure if that last makes sense, since I haven't yet mastered intransitive verbs)
The first one makes sense. The second does not.