Traditional grammar makes a binary distinction between intransitive verbs that cannot take a direct object (such as "fall" or "sit" in English) and transitive verbs that take one direct object (such as "throw", "injure", "kiss" in English). In practice, many languages (including English) interpret the category more flexibly, allowing: ditransitive verbs, verbs that have two objects; or even ambitransitive verbs, verbs that can be used as both a transitive verb and an intransitive verb. Further, some verbs may be idiomatically transitive, while, technically, intransitive. This may be observed in the verb "walk" in the idiomatic expression "To walk the dog".