For example, X → jingtian X 1 , X 1 this year , seems to capture the use of jingtian/this year as a temporal modifier when building linguistic constituents such as noun phrases (the election this year) or verb phrases (voted in the primary this year).
it is important to observe that nothing in the Hiero framework actually requires nonterminal symbols to cover linguistically sensible constituents, and in practice they frequently do not.