But as the groups got bigger and bigger, the amount of time spent in grooming activities also had to be 63 to maintain its effectiveness. Clearly, a more 64 kind of grooming was needed, and thus language evolved as a kind of vocal(有声的)grooming which allowed humans to develop relationship with ever-larger groups by exchanging information over a wider network of 15 individuals than would be possible by one-to-one 65 contact.