The other forms are produced from these and from the active forms periphrastically. Other tenses can be indicated periphrastically. The perfect tense passive is formed periphrastically using a perfect participle and the verb . Future tense forms, however, are impossible and can only be expressed periphrastically. Causatives may also be formed periphrastically with the verb /moka/. Other tenses can be formed periphrastically, with the use of auxiliary verbs. All other mood/tense/aspect combinations are produced periphrastically using the auxiliary "kam" (have) and indeclinable particles. Other languages, including English, express the passive voice periphrastically, using an auxiliary verb. Synthetically conjugated verbs like 'come' can also be conjugated periphrastically ("etortzen naiz"). Futurity of action is expressed periphrastically with one of the auxiliary verbs "will" or "shall". For many adjectives, these are formed periphrastically, using the adverbs "more" and / "most".