改否定句是用doesn‘t often do还是often doesn’t do？

老师说的和我不一样

doesn‘t often do

often要放在助动词后

he seldom does his homewok at home.原句的意思是说他经常在家写作业，因此改为否定句应该是他很少（不经常）在家写作业。 he often doesn't do his homework at home，这个句子不通顺。 c :意思是说他喜欢海豚，他认为他既不丑也不蠢。